OBJECTIVES:

To compare survival rates and age at death among very preterm infants in 10 national and regional neonatal networks.

METHODS:

A cohort study of very preterm infants, born between 24 and 29 weeks’ gestation and weighing <1500 g, admitted to participating neonatal units between 2007 and 2013 in the International Network for Evaluating Outcomes of Neonates. Survival was compared by using standardized ratios (SRs) comparing survival in each network to the survival estimate of the whole population.

RESULTS:

Network populations differed with respect to rates of cesarean birth, exposure to antenatal steroids and birth in nontertiary hospitals. Network SRs for survival were highest in Japan (SR: 1.10; 99% confidence interval: 1.08–1.13) and lowest in Spain (SR: 0.88; 99% confidence interval: 0.85–0.90). The overall survival differed from 78% to 93% among networks, the difference being highest at 24 weeks’ gestation (range 35%–84%). Survival rates increased and differences between networks diminished with increasing gestational age (GA) (range 92%–98% at 29 weeks’ gestation); yet, relative differences in survival followed a similar pattern at all GAs. The median age at death varied from 4 days to 13 days across networks.

CONCLUSIONS:

The network ranking of survival rates for very preterm infants remained largely unchanged as GA increased; however, survival rates showed marked variations at lower GAs. The median age at death also varied among networks. These findings warrant further assessment of the representativeness of the study populations, organization of perinatal services, national guidelines, philosophy of care at extreme GAs, and resources used for decision-making.

What’s Known on This Subject:

Survival rates of very preterm infants vary among regions. International collaborations have been established to compare outcomes, but population-based comparisons have been difficult to accomplish.

What This Study Adds:

This study shows variations in survival and age at death among very preterm infants in 10 national neonatal networks and provides insight into differences that affect comparisons. The findings warrant investigation of the organization of perinatal care in participating networks.

Preterm birth remains the major cause of infant mortality in high-income countries.1 Studies published in the last decade have shown variability in survival rates and outcomes among health care settings as well as within countries.2,12 Results from the Euro-Peristat project showed that neonatal survival among very preterm infants improved by 29% between 2004 and 2010 in 18 European countries, including those with high baseline survival.13 Such comparisons of different health care organizations worldwide can deliver important benchmarking information and potentially provide impetus for reviewing clinical practices, norms, and guidelines.

The International Network for Evaluating Outcomes of Neonates (iNeo) is a nonprofit collaboration among 10 national and regional neonatal networks: the Australian and New Zealand Neonatal Network (ANZNN), the Canadian Neonatal Network (CNN), the Finnish Medical Birth Register (FinMBR), the Israel Neonatal Network (INN), Neonatal Research Network Japan (NRNJ), the Spanish Neonatal Network (SEN1500), Sweden’s National Quality Registry for Neonatal Care (SNQ), the Swiss Neonatal Network (SwissNeoNet), Tuscany Neonatal Network (TuscanNN), and the United Kingdom Neonatal Collaborative (UKNC). The overarching aim of the iNeo collaboration is to compare outcomes of very preterm infants, understand reasons for variations, and, if possible, identify areas for improvement in care practices based on findings.14 

By using the iNeo data set, the objective of this study was to compare gestational age (GA)-specific survival rates for very preterm infants in all neonatal networks currently participating in the iNeo partnership and to explore variations in postnatal age at death among the very preterm population.

This cohort study included infants born at 24 to 29 weeks’ gestation, weighing <1500 g at birth, and registered in participating network databases from 2007 to 2013 (2008–2013 for UKNC, 2009–2013 for TuscanNN). The criterion of 1500 g was used because some networks limited their data collection to infants with a birth weight <1500 g. Stillborn infants and delivery room deaths were not included because all networks do not routinely collect data on these infants. Because of variability in practices and philosophy of care provision at <24 weeks’ GA, we only included neonates born at ≥24 weeks’ gestation. Infants admitted for the first time to neonatal care after 36 weeks’ corrected GA were excluded. Data on infant characteristics and outcomes were extracted, as previously described.14 Transferred infants were included only once.

Population coverage of networks deviate from national birth statistics for various reasons. All neonatal units in Finland, New Zealand, and Tuscany participate in their national and regional neonatal networks; however, in Australia, apart from all tertiary neonatal units, only a few lower-level units participate in the ANZNN. In Canada, only tertiary neonatal units participate in the CNN. In Israel, all neonatal units participate, but infants with a birth weight >1500 g are not included. In Japan and Spain, not all neonatal units participate in the national networks. In Sweden, all neonatal units presently participate in the SNQ; however, the Skåne region is not included in this study because it joined in 2011. In Switzerland, all tertiary and large secondary (level IIB) neonatal units participate in SwissNeoNet. In the United Kingdom, all neonatal units in England, Wales, and Scotland participate in the UKNC; however, a number of neonatal units have not consented for participation in iNeo.

GA was determined by the best estimate based on either early ultrasound, the timing of the last menstrual period, or physical examination after birth, in that order. Antenatal steroid use was defined as maternal receipt of antenatal steroids at any time before birth. Birth weight z scores were calculated according to birth weight references appropriate for each country.15,17 Mode of delivery was recorded as vaginal or cesarean. Multiple births included twins and higher-order multiples.

The primary outcome was survival to discharge from the hospital for infants admitted to neonatal care. Survival to transfer to a step-down hospital was used when follow-up was available only until the transfer. We analyzed survival in 1-week GA increments. As a secondary outcome, we compared postnatal age at death among nonsurvivors. Neonatal morbidities among iNeo survivors have been recently published.18 

For most networks, defined data elements were either collected from patient records by designated abstractors according to network policies or entered directly into a central online database by participating units. For the UKNC, data were obtained from the National Neonatal Research Database managed by the Neonatal Data Analysis Unit, which contains a predefined extract from electronic patient records used in UK neonatal units. Finnish data were collected from the Medical Birth Register kept at the National Institute for Health and Welfare.

Background characteristics of infants were compared by using the Pearson χ2 test for categorical variables and the analysis of variance F test for continuous variables. Standardized ratios (SRs) were computed by using the indirect standardization approach. The pooled estimate of survival for the whole population was used as a standard. Each network was then compared with this standard, computed as the sum of predicted probabilities from a multivariable logistic regression model with adjustment for GA (linear), birth weight z score (linear and quadratic), multiple births, and sex. SR estimates were displayed graphically to identify countries with survival rates greater than and less than the average rate of all others with 99% confidence intervals (CIs). Because the SR estimate is calculated in relation to all other networks combined, it is not directly comparable among networks. No adjustment was made for the administration of antenatal steroids, cesarean birth, or birth in a nontertiary hospital because these are practice-related elements, and adjustment of these variables can lead to biased estimates in favor of underperforming systems. Missing data were not imputed. All statistical analyses and plots were conducted by using SAS version 9.3 (SAS Institute Inc, Cary, NC) or R version 2.2.

All iNeo collaborators hold relevant research ethics approvals for their data collection. Separate data sharing agreements were obtained from the executive committees of each network and the iNeo Coordinating Center in Toronto, Canada. Ethics approval for the iNeo collaboration was obtained from the Research Ethics Board at Mount Sinai Hospital in Toronto, Canada.

A total of 91 835 infants born between 24 and 29 weeks’ gestation were identified in the iNeo database during the study period. After excluding infants with a birth weight >1500 g (N = 3070) and infants admitted to neonatal care after 36 weeks’ corrected GA (N = 438), the final population consisted of 88 327 infants. The variations in care provision and organization of care among the networks are provided in Table 1, as reported by network directors. Table 2 describes characteristics of infants in each participating network. The population coverage of iNeo networks compared with national birth statistics ranged from 61% in Japan (NRNJ) to 100% in Sweden (SNQ), Switzerland (SwissNeoNet), and Tuscany (TuscanNN). Infant characteristics (including exposure to antenatal steroids, cesarean birth, and birth in a nontertiary hospital) were markedly different among networks.

TABLE 1

Characteristics of the 10 National Neonatal Networks Participating in the iNeo

ANZNNCNNFin MBRINNNRNJSEN1500SNQaSwissNeoNetTuscanNNbUKNCcTotal
Approximate no. of births per year 360 000 380 000 60 000 160 000 1 080 000 480 000 90 000 80 000 30 000 690 000 3 410 000 
Units from which data are included in iNeob 56 28 30 27 73 61 28 12 24 131 470 
Tertiary neonatal units in the country or region 29 28 23 93 50 49 300 
Delivery room deaths included in database No Partial Yes Yes Yes Yes Yes Yes Yes Partial — 
Data from step-down units included Yes No Yes Yes No Yes Yes Yes Yes Yes — 
Proportion of infants in network compared with national birth statisticsd 92.5% 92.5% 99.1% 95.0% 61.1% 76.1%e 100% 99.7% 100% 73.5% 75.6% 
ANZNNCNNFin MBRINNNRNJSEN1500SNQaSwissNeoNetTuscanNNbUKNCcTotal
Approximate no. of births per year 360 000 380 000 60 000 160 000 1 080 000 480 000 90 000 80 000 30 000 690 000 3 410 000 
Units from which data are included in iNeob 56 28 30 27 73 61 28 12 24 131 470 
Tertiary neonatal units in the country or region 29 28 23 93 50 49 300 
Delivery room deaths included in database No Partial Yes Yes Yes Yes Yes Yes Yes Partial — 
Data from step-down units included Yes No Yes Yes No Yes Yes Yes Yes Yes — 
Proportion of infants in network compared with national birth statisticsd 92.5% 92.5% 99.1% 95.0% 61.1% 76.1%e 100% 99.7% 100% 73.5% 75.6% 

—, not applicable.

a

Sweden, excluding the Skåne region.

b

2009–2013.

c

2008–2013.

d

Proportion of infants born at 24–29 weeks’ gestation in each network compared with corresponding numbers in national birth statistics.

e

Of all infants born at <28 weeks’ GA.

TABLE 2

Population Characteristics of Infants (24–29 Weeks’ Gestation, Birth Weight <1500 g) Born Between 2007 and 2013 and Admitted to Neonatal Care in iNeo Contributing Networks

ANZNNCNNFinMBRINNNRNJSEN1500SNQaSwissNeoNetTuscanNNbUKNCcTotal
No. of neonates included in database 14 043 13 688 1728 5441 18 431 10 695 3346 2775 737 20 951 91 835 
Infants excluded due to birth weight >1500 g, n (%) 778 (5.5) 717 (5.2) 95 (5.5) 0 (0) 5 (0.03) 148 (1.4) 222 (6.6) 97 (3.5) 32 (4.3) 976 (4.7) 3070 (3.3) 
Admitted at >36 wks’ gestation, n (%) 26 (0.2) 83 (0.6) 0 (0) 0 (0) 5 (0.03) 321 (3.0) 0 (0) 3 (0.1) 0 (0) 0 (0) 438 (0.5) 
Study infants, n (%) 13 239 (94.3) 12 888 (94.2) 1633 (94.5) 5441 (100) 18 421 (99.9) 10 226 (95.6) 3124 (93.4) 2675 (96.4) 705 (95.7) 19 975 (95.3) 88 327 (96.2) 
GA (wks), mean (SD)d 27.0 (1.6) 26.9 (1.6) 27.0 (1.6) 27.0 (1.6) 26.9 (1.7) 27.1 (1.6) 27.0 (1.6) 27.1 (1.6) 27.0 (1.7) 27.0 (1.6) 27.0 (1.6) 
Proportion of infants 24 wks’ GA, n (%)d 1229 (9.3) 1191 (9.2) 156 (9.6) 482 (8.9) 2082 (11.3) 866 (8.5) 292 (9.3) 186 (7.0) 94 (13.3) 2053 (10.3) 8631 (9.8) 
Birth weight (g), mean (SD)d 993 (251) 986 (246) 980 (259) 972 (247) 927 (256) 978 (247) 986 (256) 961 (254) 940 (257) 976 (243) 969 (251) 
Birth weight z score, mean (SD)d 0.01 (0.95) −0.09 (0.83) −0.18 (0.91) −0.10 (0.83) −0.17 (0.99) −0.08 (0.98) −0.12 (0.86) −0.17 (0.82) 0.07 (0.97) −0.18 (0.93) −0.11 (0.93) 
Multiple births, n (%),d [missing data] 3758 (28.4) [11] 3706 (28.8) [9] 484 (29.6) 2133 (39.2) 3809 (20.7) 3071 (30.0) 898 (28.7) 802 (30.0) 222 (31.5) [1] 5305 (26.6) [7] 24 188 (27.4) [28] 
Male sex, n (%), [missing data] 7064 (53.4) [9] 6985 (54.2) [22] 862 (52.8) 2952(54.3) 9877 (53.6) [8] 5461 (53.4) 1697 (54.3) [2] 1401 (52.4) [1] 363 (51.5) 10 740 (53.8) [9] 47 402 (53.7) [51] 
Any antenatal steroid, n (%),d [missing data] 11 818 (89.3) [185] 10 994 (85.3) [429] 1537 (94.1) [17] 4098 (75.3) [3] 9901 (53.7) [556] 8700 (85.1) [170] 2616 (83.7) 2400 (89.7) [42] 607 (86.1) [5] 16 585 (83.0) [1018] 69 256 (78.4) [2425] 
Cesarean birth, n (%),d [missing data] 8101 (61.2) [61] 7703 (59.8) [96] 1144 (70.1) [4] 3877 (71.3) 14 132 (76.7) [262] 6592 (64.5) 2159 (69.1) 2146 (80.2) 492 (69.8) 9903 (49.6) [1725] 56 249 (63.7) [2151] 
Born in nontertiary hospital, n (%),d [missing data] 1791 (13.5) 2234 (17.3) [16] 79 (4.8) 63(1.2) 1193 (6.5) 562 (5.5) 321 (10.3) [13] 127 (4.7) 115 (16.3) Not applicable 6485 (9.5) [29] 
ANZNNCNNFinMBRINNNRNJSEN1500SNQaSwissNeoNetTuscanNNbUKNCcTotal
No. of neonates included in database 14 043 13 688 1728 5441 18 431 10 695 3346 2775 737 20 951 91 835 
Infants excluded due to birth weight >1500 g, n (%) 778 (5.5) 717 (5.2) 95 (5.5) 0 (0) 5 (0.03) 148 (1.4) 222 (6.6) 97 (3.5) 32 (4.3) 976 (4.7) 3070 (3.3) 
Admitted at >36 wks’ gestation, n (%) 26 (0.2) 83 (0.6) 0 (0) 0 (0) 5 (0.03) 321 (3.0) 0 (0) 3 (0.1) 0 (0) 0 (0) 438 (0.5) 
Study infants, n (%) 13 239 (94.3) 12 888 (94.2) 1633 (94.5) 5441 (100) 18 421 (99.9) 10 226 (95.6) 3124 (93.4) 2675 (96.4) 705 (95.7) 19 975 (95.3) 88 327 (96.2) 
GA (wks), mean (SD)d 27.0 (1.6) 26.9 (1.6) 27.0 (1.6) 27.0 (1.6) 26.9 (1.7) 27.1 (1.6) 27.0 (1.6) 27.1 (1.6) 27.0 (1.7) 27.0 (1.6) 27.0 (1.6) 
Proportion of infants 24 wks’ GA, n (%)d 1229 (9.3) 1191 (9.2) 156 (9.6) 482 (8.9) 2082 (11.3) 866 (8.5) 292 (9.3) 186 (7.0) 94 (13.3) 2053 (10.3) 8631 (9.8) 
Birth weight (g), mean (SD)d 993 (251) 986 (246) 980 (259) 972 (247) 927 (256) 978 (247) 986 (256) 961 (254) 940 (257) 976 (243) 969 (251) 
Birth weight z score, mean (SD)d 0.01 (0.95) −0.09 (0.83) −0.18 (0.91) −0.10 (0.83) −0.17 (0.99) −0.08 (0.98) −0.12 (0.86) −0.17 (0.82) 0.07 (0.97) −0.18 (0.93) −0.11 (0.93) 
Multiple births, n (%),d [missing data] 3758 (28.4) [11] 3706 (28.8) [9] 484 (29.6) 2133 (39.2) 3809 (20.7) 3071 (30.0) 898 (28.7) 802 (30.0) 222 (31.5) [1] 5305 (26.6) [7] 24 188 (27.4) [28] 
Male sex, n (%), [missing data] 7064 (53.4) [9] 6985 (54.2) [22] 862 (52.8) 2952(54.3) 9877 (53.6) [8] 5461 (53.4) 1697 (54.3) [2] 1401 (52.4) [1] 363 (51.5) 10 740 (53.8) [9] 47 402 (53.7) [51] 
Any antenatal steroid, n (%),d [missing data] 11 818 (89.3) [185] 10 994 (85.3) [429] 1537 (94.1) [17] 4098 (75.3) [3] 9901 (53.7) [556] 8700 (85.1) [170] 2616 (83.7) 2400 (89.7) [42] 607 (86.1) [5] 16 585 (83.0) [1018] 69 256 (78.4) [2425] 
Cesarean birth, n (%),d [missing data] 8101 (61.2) [61] 7703 (59.8) [96] 1144 (70.1) [4] 3877 (71.3) 14 132 (76.7) [262] 6592 (64.5) 2159 (69.1) 2146 (80.2) 492 (69.8) 9903 (49.6) [1725] 56 249 (63.7) [2151] 
Born in nontertiary hospital, n (%),d [missing data] 1791 (13.5) 2234 (17.3) [16] 79 (4.8) 63(1.2) 1193 (6.5) 562 (5.5) 321 (10.3) [13] 127 (4.7) 115 (16.3) Not applicable 6485 (9.5) [29] 
a

Sweden, excluding the Skåne region.

b

2009–2013.

c

2008–2013.

d

P < .001.

Of the 88 327 included infants, 77 172 (87%) survived to discharge. Overall survival rates varied from 78% in SEN1500 to 93% in NRNJ (Table 3). The differences in percentage points between networks with the lowest and highest survival rates were 49% at 24 weeks’ gestation (INN 35%, NRNJ 84%), 32% at 25 weeks (INN 57%, NRNJ 89%), 20% at 26 weeks (73% SEN1500, 93% NRNJ), 12% at 27 weeks (82% SEN1500, 94% NRNJ), 8% at 28 weeks (89% SEN1500, 97% NRNJ), and 6% at 29 weeks (92% SEN1500, 98% SwissNeoNet). Survival increased as GA increased in all networks. Internetwork ranking of the survival rate followed a similar pattern at all GAs. The GA-specific survival rates are presented graphically in Fig 1.

TABLE 3

GA-Specific Survival Rates Among Infants (24–29 Weeks’ Gestation, Birth Weight <1500 g) Born Between 2007 and 2013 and Admitted to Neonatal Care in the iNeo Networks

ANZNN n/N (%)CNN n/N (%)FinMBR n/N (%)INN n/N (%)NRNJ n/N (%)SEN1500 n/N (%)SNQan/N (%)SwissNeoNet n/N (%)TuscanNNbn/N (%)UKNCcn/N (%)Total n/N (%)
GA 240/7–246/7 793/1229 (64.5) 736/1191 (61.8) 110/156 (70.5) 168/482 (34.9) 1743/2082 (83.7) 312/866 (36.0) 205/292 (70.2) 107/186 (57.5) 50/94 (53.2) 1308/2053 (63.7) 5532/8631 (64.1) 
GA 250/7–256/7 1321/1655 (79.8) 1445/1829 (79.0) 155/197 (78.7) 381/664 (57.4) 2155/2413 (89.3) 714/1200 (59.5) 335/395 (84.8) 214/319 (67.1) 58/81 (71.6) 1815/2366 (76.7) 8593/11 119 (77.3) 
GA 260/7–266/7 1853/2117 (87.5) 1777/2043 (87.0) 196/231 (84.8) 659/847 (77.8) 2658/2850 (93.3) 1147/1568 (73.2) 450/509 (88.4) 384/458 (83.8) 60/78 (76.9) 2626/3091 (85.0) 11 810/13 792 (85.6) 
GA 270/7–276/7 2163/2346 (92.2) 2208/2412 (91.5) 295/329 (89.7) 809/947 (85.4) 3116/3301 (94.4) 1507/1842 (81.8) 539/582 (92.6) 434/478 (90.8) 107/127 (84.3) 3289/3657 (89.9) 14 467/16 021 (90.3) 
GA 280/7–286/7 2785/2939 (94.8) 2559/2703 (94.7) 336/362 (92.8) 1063/1156 (92.0) 3714/3850 (96.5) 1959/2210 (88.6) 624/672 (92.9) 551/581 (94.8) 140/148 (94.6) 4068/4383 (92.8) 17 799/19 004 (93.7) 
GA 290/7–296/7 2870/2953 (97.2) 2626/2710 (96.9) 347/358 (96.9) 1270/1345 (94.4) 3806/3925 (97.0) 2348/2540 (92.4) 650/674 (96.4) 637/653 (97.5) 170/177 (96.0) 4247/4425 (96.0) 18 971/19 760 (96.0) 
GA 240/7–296/7 11 785/13 239 (89.0) 11 351/12 888 (88.1) 1439/1633 (88.1) 4350/5441 (79.9) 17 192/18 421 (93.3) 7987/10 226 (78.1) 2803/3124 (89.7) 2327/2675 (87.0) 585/705 (83.0) 17 353/19 975 (86.9) 77 172/88 327 (87.4) 
ANZNN n/N (%)CNN n/N (%)FinMBR n/N (%)INN n/N (%)NRNJ n/N (%)SEN1500 n/N (%)SNQan/N (%)SwissNeoNet n/N (%)TuscanNNbn/N (%)UKNCcn/N (%)Total n/N (%)
GA 240/7–246/7 793/1229 (64.5) 736/1191 (61.8) 110/156 (70.5) 168/482 (34.9) 1743/2082 (83.7) 312/866 (36.0) 205/292 (70.2) 107/186 (57.5) 50/94 (53.2) 1308/2053 (63.7) 5532/8631 (64.1) 
GA 250/7–256/7 1321/1655 (79.8) 1445/1829 (79.0) 155/197 (78.7) 381/664 (57.4) 2155/2413 (89.3) 714/1200 (59.5) 335/395 (84.8) 214/319 (67.1) 58/81 (71.6) 1815/2366 (76.7) 8593/11 119 (77.3) 
GA 260/7–266/7 1853/2117 (87.5) 1777/2043 (87.0) 196/231 (84.8) 659/847 (77.8) 2658/2850 (93.3) 1147/1568 (73.2) 450/509 (88.4) 384/458 (83.8) 60/78 (76.9) 2626/3091 (85.0) 11 810/13 792 (85.6) 
GA 270/7–276/7 2163/2346 (92.2) 2208/2412 (91.5) 295/329 (89.7) 809/947 (85.4) 3116/3301 (94.4) 1507/1842 (81.8) 539/582 (92.6) 434/478 (90.8) 107/127 (84.3) 3289/3657 (89.9) 14 467/16 021 (90.3) 
GA 280/7–286/7 2785/2939 (94.8) 2559/2703 (94.7) 336/362 (92.8) 1063/1156 (92.0) 3714/3850 (96.5) 1959/2210 (88.6) 624/672 (92.9) 551/581 (94.8) 140/148 (94.6) 4068/4383 (92.8) 17 799/19 004 (93.7) 
GA 290/7–296/7 2870/2953 (97.2) 2626/2710 (96.9) 347/358 (96.9) 1270/1345 (94.4) 3806/3925 (97.0) 2348/2540 (92.4) 650/674 (96.4) 637/653 (97.5) 170/177 (96.0) 4247/4425 (96.0) 18 971/19 760 (96.0) 
GA 240/7–296/7 11 785/13 239 (89.0) 11 351/12 888 (88.1) 1439/1633 (88.1) 4350/5441 (79.9) 17 192/18 421 (93.3) 7987/10 226 (78.1) 2803/3124 (89.7) 2327/2675 (87.0) 585/705 (83.0) 17 353/19 975 (86.9) 77 172/88 327 (87.4) 
a

Sweden, excluding the Skåne region.

b

2009–2013.

c

2008–2013.

FIGURE 1

GA-specific survival for infants (24–29 weeks’ gestation, birth weight <1500 g) born between 2007 and 2013 and admitted to neonatal care in the iNeo networks.

FIGURE 1

GA-specific survival for infants (24–29 weeks’ gestation, birth weight <1500 g) born between 2007 and 2013 and admitted to neonatal care in the iNeo networks.

Close modal

Estimated SRs comparing survival in each network to all other networks were higher in NRNJ (SR: 1.10; 99% CI: 1.08–1.13) and lower in INN (SR: 0.91; 99% CI: 0.87–0.95) and SEN1500 (SR: 0.88; 99%: CI 0.85–0.90) and overlapped with the 99% CI in ANZNN (SR: 1.01; 99% CI: 0.99–1.04), CNN (SR: 1.01; 99% CI: 0.99–1.04), FinMBR (SR: 1.01; 99% CI: 0.94–1.08), SNQ (SR: 1.03; 99% CI: 0.98–1.08), SwissNeoNet (SR: 0.99; 99% CI: 0.94–1.04), TuscanNN (SR: 0.95; 99% CI: 0.85–1.05), and UKNC (SR: 0.99; 99% CI: 0.97–1.01) (Fig 2). Pairwise comparisons among networks are presented in Supplemental Table 5.

FIGURE 2

SRs of survival for infants (24–29 weeks’ gestation, birth weight <1500 g) born during the study period (2007–2013) and admitted to neonatal care in each iNeo network. a SRs comparing the survival in each network to all other networks combined. Vertical bars are the estimated 99% CIs of the SRs. The dotted curves represent the 99% control limits expected under the null hypothesis of similar outcome rates (SR = 1).

FIGURE 2

SRs of survival for infants (24–29 weeks’ gestation, birth weight <1500 g) born during the study period (2007–2013) and admitted to neonatal care in each iNeo network. a SRs comparing the survival in each network to all other networks combined. Vertical bars are the estimated 99% CIs of the SRs. The dotted curves represent the 99% control limits expected under the null hypothesis of similar outcome rates (SR = 1).

Close modal

A total of 11 155 infants did not survive to discharge. Age at death was available for 10 839 (97%) neonates, which is presented as a function of postnatal age in Fig 3 and Supplemental Fig 4. Median age at death for the entire population was 8 days, varying from 4 days to 13 days in the FinMBR and NRNJ, respectively (Table 4). Among deaths, 14.6% occurred before 24 hours of age (6.9% TuscanNN, 26.8% FinMBR), 29.7% at 1 to 6 days of age (23.8% NRNJ, 44.4% SwissNeoNet), 32.1% at 7 to 27 days of age (21.6% FinMBR, 37.3% TuscanNN), and 23.6% after 28 days of age (14.4% SwissNeoNet, 32.7% NRNJ). Overall, the median postnatal age at death for the entire population remained stable at 8 days to 9 days over the study duration.

FIGURE 3

Age at death among nonsurviving infants (24–29 weeks’ gestation, birth weight <1500 g) born between 2007 and 2013 and admitted to neonatal care in each iNeo network. a Truncated to 100 days.

FIGURE 3

Age at death among nonsurviving infants (24–29 weeks’ gestation, birth weight <1500 g) born between 2007 and 2013 and admitted to neonatal care in each iNeo network. a Truncated to 100 days.

Close modal
TABLE 4

Age at Death Among Nonsurviving Infants (GA 24–29 Weeks’ Gestation, Birth Weight <1500 g) Born Between 2007 and 2013 and Admitted to Neonatal Care in Each iNeo Network

ANZN N, N = 1450CNN, N = 1531FinMBR, N = 194INN, N = 1091NRNJ, N = 1206SEN1500, N = 1986SNQ, N = 311SwissNeoNet, N = 347TuscanNN,aN = 102UKNC,bN = 2621All, N = 10 839
Median (IQR) age at death, d 8 (3–30) 10 (3–26) 4 (1–15) 7 (3–19) 13 (3–42) 8 (3–20) 7 (2–24) 6 (2–16) 8 (2–19) 8 (2–28) 8 (3–26) 
No. missing 23 253 10 18 316 
Age at death <1 d,cn (%) 146 (10.0) 139 (9.1) 52 (26.8) 179 (16.4) 155 (12.9) 266 (13.4) 52 (16.7) 34 (9.8) 7 (6.9) 554 (21.1) 1584 (14.6) 
Age at death 1–6 d, n (%) 499 (34.4) 478 (31.2) 70 (36.1) 343 (31.4) 287 (23.8) 627 (31.6) 97 (31.2) 154 (44.4) 40 (39.2) 627 (23.9) 3222 (29.7) 
Age at death 7–27 d, n (%) 409 (28.2) 558 (36.5) 42 (21.6) 358 (32.8) 370 (30.7) 732 (36.9) 92 (29.6) 109 (31.4) 38 (37.3) 771 (29.4) 3479 (32.1) 
Age at deathc ≥28 d, n (%) 396 (27.3) 356 (23.3) 30 (15.5) 211 (19.3) 394 (32.7) 361 (18.2) 70 (22.5) 50 (14.4) 17 (16.7) 669 (25.5) 2554 (23.6) 
Median age at death in days according to years 
 2007 9.5 7.5 11 — — 
 2008 11.5 14 10 — 
 2009 6.5 15 16 
 2010 10 11 3.5 12 24 
 2011 12.5 13 
 2012 10 10 16 11 
 2013 10 21 
ANZN N, N = 1450CNN, N = 1531FinMBR, N = 194INN, N = 1091NRNJ, N = 1206SEN1500, N = 1986SNQ, N = 311SwissNeoNet, N = 347TuscanNN,aN = 102UKNC,bN = 2621All, N = 10 839
Median (IQR) age at death, d 8 (3–30) 10 (3–26) 4 (1–15) 7 (3–19) 13 (3–42) 8 (3–20) 7 (2–24) 6 (2–16) 8 (2–19) 8 (2–28) 8 (3–26) 
No. missing 23 253 10 18 316 
Age at death <1 d,cn (%) 146 (10.0) 139 (9.1) 52 (26.8) 179 (16.4) 155 (12.9) 266 (13.4) 52 (16.7) 34 (9.8) 7 (6.9) 554 (21.1) 1584 (14.6) 
Age at death 1–6 d, n (%) 499 (34.4) 478 (31.2) 70 (36.1) 343 (31.4) 287 (23.8) 627 (31.6) 97 (31.2) 154 (44.4) 40 (39.2) 627 (23.9) 3222 (29.7) 
Age at death 7–27 d, n (%) 409 (28.2) 558 (36.5) 42 (21.6) 358 (32.8) 370 (30.7) 732 (36.9) 92 (29.6) 109 (31.4) 38 (37.3) 771 (29.4) 3479 (32.1) 
Age at deathc ≥28 d, n (%) 396 (27.3) 356 (23.3) 30 (15.5) 211 (19.3) 394 (32.7) 361 (18.2) 70 (22.5) 50 (14.4) 17 (16.7) 669 (25.5) 2554 (23.6) 
Median age at death in days according to years 
 2007 9.5 7.5 11 — — 
 2008 11.5 14 10 — 
 2009 6.5 15 16 
 2010 10 11 3.5 12 24 
 2011 12.5 13 
 2012 10 10 16 11 
 2013 10 21 

—, not applicable.

a

2009–2013.

b

2008–2013.

c

Percentage of all nonsurvivors in each network.

In this large, multinational study, we identified significant differences in the survival of very preterm infants, particularly at 24 to 27 weeks’ gestation. Survival increased and differences in survival between networks decreased with increasing GA, whereas internetwork ranking of survival remained relatively unchanged at each gestation. The median postnatal age at death ranged from 4 days to 13 days within networks.

The iNeo networks reached survival ranging from 78% to 93% in the very preterm infant population. Other international studies have shown similar survival rates: 77% to 91% for infants born at 22 to 31 weeks’ gestation in the European Health Care Outcomes, Performance and Efficiency (study in 2006–2008,9 83% for infants born at 24 to 28 weeks’ gestation in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network (NICHD NRN) in 2008–2012,2 and 74% to 94% for infants born at 24 to 29 weeks’ gestation in the Effective Perinatal Intensive Care in Europe (EPICE) study in 2011.19 The European Health Care Outcomes, Performance and Efficiency study can also be used to validate our ranking order related to 3 countries because the ranking order of Sweden, Finland, and Italy was the same in both studies.

Some differences have to be noted in the study designs, such as the inclusion of delivery room deaths and limitation to tertiary hospitals in the NICHD NRN. The EPICE study also included stillborn infants and delivery room deaths, but the proportion of live-born infants could be extracted from their data. Including nontertiary hospitals is likely to decrease overall survival rates, but excluding delivery room deaths is likely to overestimate survival.

Internetwork differences in survival were largest among infants born at 24 weeks’ gestation and decreased with increasing GA. However, networks with the lowest survival rates among 24-week infants continued to display low survival rates in relation to the other networks at almost all GA groups. Similarly, Berger et al4 reported that among Swiss university hospitals, survival differences were most pronounced among infants born at 23 to 25 weeks’ gestation, and the interunit rank remained consistent for more mature infants. We do not have detailed data for an in-depth explanation of these differences, but in addition to variable population coverage, they may be related to organizational factors, such as regionalization, staffing, philosophy of care provision, willingness to offer palliative care, and withdrawal of intensive support and other resources.20,21 Furthermore, it is well recognized that the approach to active care largely explains differences in survival in infants at extremely low GAs.7,22 We only included infants born at 24 to 29 weeks’ gestation, assuming that participating neonatal units would provide active care to these neonates. It has been suggested by researchers in other studies that adopting a more active approach to extremely low GAs also results in increased survival in higher-GA groups.23,25 

The nonsurvivors died later (median of 8 days) in our study compared with those in the NICHD NRN (median of 3 days) from 2008 to 2011.26 However, it must be acknowledged that the infants in the NICHD NRN study were more immature (median GA of 25.7 weeks for all live births). Mohamed et al27 found a significant increase in the mean age at death (from 6.6 days to 8.7 days) in very low birth weight infants in a large, national sample in the United States between 1997 and 2004. They also showed that infants with a birth weight of <500 g died earlier than others.

Finally, we also identified differences in the age at death of nonsurvivors among the iNeo networks. The reasons for death vary at different postnatal ages. In the NICHD NRN study,26 the predominant causes of death were reported to be immaturity in the first 12 hours of life, followed by respiratory distress syndrome during the first 2 weeks to 4 weeks, necrotizing enterocolitis between 0.5 months and 2 months, and bronchopulmonary dysplasia after 2 months of age. Corchia et al28 reported that respiratory causes and intraventricular hemorrhage were the predominant causes of death within the first 2 weeks of life, and late-onset infections and gastrointestinal causes became more prevalent after the first week. We did not have data on the causes of death, and therefore, we were unable to find reasons for differences in postnatal age at death. However, we believe that these differences are important to know and understand from health services and administrative perspectives. Other possible causes of differences in postnatal age at death can be related to the care and diagnostics during pregnancy, in addition to perinatal and neonatal care. For instance, a region with a restrictive pregnancy termination policy had a higher proportion of deaths because of congenital anomalies in the Models of OrganiSing Access to Intensive Care for very preterm births study.29 In addition, policies and attitudes regarding redirection of care can be different in different countries and regions.30 

Our study has several acknowledgeable strengths. We used a large, multinational, population-based cohort of very preterm infants. Data collection was standardized by using a common data set and providing clear definitions for variables before analysis. Including data from 7 consecutive years decreased the influence of random variations. All iNeo contributors have well-established data gathering systems, conduct benchmarking and quality-improvement activities, have similar antenatal health care resources, and contain nearly universal access to antenatal follow-up and public delivery hospitals. Finally, survival as the primary outcome is objective and not biased by complex definitions.

However, we must also recognize our limitations. First, varying national coverage of births in participating networks might have influenced our results. It is likely that units not participating or not providing data may have lower survival rates compared with participating units. Preliminary data from Japan suggest that units not contributing to the NRNJ have mortality rates that are 1.1- to 1.5-fold higher than NRNJ contributors for infants of <27 weeks’ gestation (N.M., unpublished observations). Some networks limited their data collection to infants with a birth weight of <1500 g, which led us to restrict our whole data set accordingly. This might introduce bias because some well-grown infants in the higher-GA range are excluded. However, this bias is similar in all networks, and the results were adjusted for country-specific birth weight z scores. Likewise, some networks collect data only from tertiary neonatal units, which is likely to introduce a bias because very preterm infants born in nontertiary hospitals have higher mortality rates.31 These issues should be considered when interpreting the results. Ideally, survival rates for each network should be calculated by using all deliveries of live fetuses at presentation to the hospital as the denominator, as done by the Extremely Preterm Infants in Sweden Study Group12; however, such data are not available to all iNeo contributors. Second, in some networks, data were only available until transfer to a step-down hospital. Nonetheless, death rates for very preterm infants after transfer to step-down hospitals were low in Finland because only 0.4% of the infants died after transfer but before discharge from the hospital. In Canada, Synnes et al32 reported a 0.7% death rate between discharge from tertiary neonatal care and 18 months to 24 months of age. Third, data on delivery room deaths and stillbirths were not available; therefore, the results may not be comparable to other groups and should be used cautiously for counseling. Fourth, data on maternal conditions (eg, hypertensive disorders, preterm rupture of membranes, and perinatal infections) and reasons for prematurity (spontaneous preterm birth versus maternal or fetal indication for preterm birth) were not available in sufficient detail to be used in the analyses. However, as shown by the EPICE group, maternal factors have little effect on the variations in outcomes.19 

In the future, similar comparisons should attempt to include all deliveries of live fetuses at presentation to the hospital. Meanwhile, networks should aim to increase the number of participating neonatal units to achieve complete population coverage, enable a comprehensive assessment of outcomes, and avoid selection biases in their evaluations.

Large variations in the survival of very preterm infants were evident among iNeo networks. Internetwork differences in survival were largest at 24 weeks’ gestation, and relative network ranking of the survival rate persisted across the studied GAs. For nonsurvivors, the median age at death varied from 4 days to 13 days among the networks. Our results warrant further assessment of the organization of perinatal services, national guidelines, philosophy of care, and resources used for decision-making.

     
  • ANZNN

    Australian and New Zealand Neonatal Network

  •  
  • CI

    confidence interval

  •  
  • CNN

    Canadian Neonatal Network

  •  
  • EPICE

    Effective Perinatal Intensive Care in Europe

  •  
  • FinMBR

    Finnish Medical Birth Register

  •  
  • GA

    gestational age

  •  
  • iNeo

    International Network for Evaluating Outcomes of Neonates

  •  
  • INN

    Israel Neonatal Network

  •  
  • NICHD NRN

    Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network

  •  
  • NRNJ

    Neonatal Research Network Japan

  •  
  • SEN1500

    Spanish Neonatal Network

  •  
  • SNQ

    Sweden’s National Quality Registry for Neonatal Care

  •  
  • SR

    standardized ratio

  •  
  • SwissNeoNet

    Swiss Neonatal Network

  •  
  • TuscanNN

    Tuscany Neonatal Network

  •  
  • UKNC

    United Kingdom Neonatal Collaborative

Dr Helenius conceptualized and designed the study, acquired, analyzed, and interpreted data, drafted the manuscript, and performed statistical analyses; Dr Shah conceptualized and designed the study, acquired, analyzed, and interpreted data, reviewed and revised the manuscript for important intellectual content, provided administrative, technical, and material support, performed statistical analyses and supervised the study; Drs Lehtonen and Sjörs conceptualized and designed the study, acquired, analyzed, and interpreted data, reviewed and revised the manuscript for important intellectual content, performed statistical analyses, and supervised the study; Drs Modi, Reichman, Morisaki, Kusuda, Lui, Darlow, Bassler, Håkansson, Vento, Rusconi, Isayama, and Lee and Mr Adams acquired, analyzed, and interpreted data and reviewed and revised the manuscript for important intellectual content; and all authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

FUNDING: Funding for International Network for Evaluating Outcomes of Neonates has been provided by a Canadian Institutes of Health Research Chair in Reproductive and Child Health Services and Policy Research (APR-126340) held by P.S.S. The Australian and New Zealand Neonatal Network is predominantly funded by membership contributions from participating centers. The Canadian Neonatal Network is funded by financial support from the Canadian Institutes of Health Research (FRN87518, PBN150642) and individual participating centers. The Finnish Medical Birth Register is governmentally funded and kept by the National Institute for Health and Welfare (THL). The Israel Neonatal Network very low birth weight infant database is partially funded by the Israel Center for Disease Control and the Ministry of Health. The Neonatal Research Network Japan is partly funded by a Health and Labour Sciences Research grant from the Ministry of Health, Labour and Welfare of Japan. Spanish Neonatal Network is supported by funds from the Spanish Neonatal Society. The National Quality Registry for Neonatal Care is funded by the Swedish Government (Ministry of Health and Social Affairs) and the body of regional health care providers (county councils). Swiss Neonatal Network is partially funded by participating units in the form of membership fees. The Tuscany Neonatal Network is funded by the Tuscany Region. The United Kingdom Neonatal Collaborative receives no core funding. The funding bodies played no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

COMPANION PAPER: A companion to this article can be found online at www.pediatrics.org/cgi/doi/10.1542/peds.2017-2808.

We acknowledge all investigators and data abstractors of the networks participating in the iNeo consortium for their diligent work. We also thank staff at the Maternal-Infant Care Research Centre in Toronto, Ontario, for organizational, statistical, and editorial support. Dr Shah had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

iNeo Group Information

ANZNN: Ross Haslam, MBBS,* Chair of the Executive Committee; Peter Marshall, MBChB, Flinders Medical Centre (Bedford Park, South Australia); Peter Schmidt, MBChB, Gold Coast University Hospital (Gold Coast, Queensland); Adam Buckmaster, MBBS, Gosford District Hospital (Gosford, New South Wales); Paul Craven, MBChB, and Koert de Waal, MBBS, PhD,* John Hunter Hospital (Newcastle, New South Wales); Karen Simmer, MBChB, PhD, Andy Gill, MBChB,* and Jane Pillow, MBBS, PhD,* King Edward Memorial and Princess Margaret Hospitals (Subiaco, Western Australia); Jacqueline Stack, MBChB, Liverpool Hospital (Liverpool, New South Wales); Lucy Cooke, MBChB, Mater Mothers’ Hospital (South Brisbane, Queensland); Dan Casalaz, MBChB, and Jim Holberton, MBBS,* Mercy Hospital for Women (Melbourne, Victoria); Charles Barfield, MBBS, Nepean Hospital, Monash Medical Centre (Melbourne, Victoria); Lyn Downe, MBBS, Vijay Shingde, MBChB (New South Wales); Michael Stewart, MBBS, MD, Newborn Emergency Transport Service (Victoria); Barbara Bajuk, MPH,* Newborn and Pregnancy Services Network (New South Wales); Andrew Berry, MBBS, Newborn and Paediatric Emergency Transport Service (New South Wales); Rod Hunt, MBChB, Royal Children’s Hospital (Parkville, Victoria); Charles Kilburn, MBChB, Royal Darwin Hospital (Darwin, Northern Territory); Tony De Paoli, MBBS, Royal Hobart Hospital (Hobart, Tasmania); Kei Lui, MBBS,* Royal Hospital for Women (Sydney, New South Wales); Mary Paradisis, MBChB, Royal North Shore Hospital (Sydney, New South Wales); Ingrid Rieger, MBChB, and Shelley Reid, RN,* Royal Prince Alfred Hospital (Syndey, New South Wales); David Cartwright, MBChB, and Pieter Koorts, MBBS, Royal Brisbane and Women’s Hospital (Brisbane, Queensland); Carl Kuschel, MBChB, and Lex Doyle, MBBS, MD, MSc, Royal Women’s Hospital (Melbourne, Victoria); Andrew Numa, MBChB, Sydney Children’s Hospital (Sydney, New South Wales); Hazel Carlisle, MBChB, Canberra Hospital (Canberra, Australian Capital Territory); Nadia Badawi, MBChB, PhD, and Robert Halliday, MBBS, The Children’s Hospital at Westmead (Sydney, New South Wales); Guan Koh, MBChB,* The Townsville Hospital (Townsville, Queensland); Steven Resnick, MBBS, Western Australia Neonatal Transport Service; Melissa Luig, MBChB, Westmead Hospital (Sydney, New South Wales); Chad Anderson, MBChB, Women’s and Children’s Hospital (South Australia); Georgina Chambers, MBA, PhD,* National Perinatal Epidemiology and Statistics Unit, University of New South Wales (Sydney, New South Wales); Adrienne Lynn, MBBS, Brian Darlow, MD, Christchurch Women’s Hospital (New Zealand); Roland Broadbent, MBChB,* Dunedin Hospital (New Zealand); Lindsay Mildenhall, MBChB, Middlemore Hospital (New Zealand); Malcolm Batten, MBChB, Auckland City Hospital (New Zealand); Jutta van den Boom, MBBS,* North Shore and Waitakere Hospitals (New Zealand); David Bourchier, MBChB, and Lee Carpenter, RN,* Waikato Hospital (New Zealand); Vaughan Richardson, MBChB, Wellington Women’s Hospital (New Zealand); Victor Samuel Rajadurai, MBBS, MD,* KK Women’s and Children’s Hospital (Little India, Singapore).

*denotes the ANZNN Executive Committee.

CNN: Prakesh S. Shah, MD, MSc (director, CNN and site investigator), Mount Sinai Hospital (Toronto, Ontario); Adele Harrison, MD, MBChB, Victoria General Hospital (Victoria, British Columbia); Anne Synnes, MDCM, MHSC, and Joseph Ting, MD, BC, Women’s Hospital and Health Centre (Vancouver, British Columbia); Zenon Cieslak, MD, Royal Columbian Hospital (New Westminster, British Columbia); Rebecca Sherlock, MD, Surrey Memorial Hospital (Surrey, British Columbia); Wendy Yee, MD, Foothills Medical Centre (Calgary, Alberta); Khalid Aziz, MBBS, MA, MEd, and Jennifer Toye, MD, Royal Alexandra Hospital (Edmonton, Alberta); Carlos Fajardo, MD, Alberta Children’s Hospital (Calgary, Alberta); Zarin Kalapesi, MD, Regina General Hospital (Regina, Saskatchewan); Koravangattu Sankaran, MD, MBBS, and Sibasis Daspal, MD, Royal University Hospital (Saskatoon, Saskatchewan); Mary Seshia, MBChB, Winnipeg Health Sciences Centre (Winnipeg, Manitoba); Ruben Alvaro, MD, St. Boniface General Hospital (Winnipeg, Manitoba); Amit Mukerji, MD, Hamilton Health Sciences Centre (Hamilton, Ontario); Orlando Da Silva, MD, MSc, London Health Sciences Centre (London, Ontario); Chuks Nwaesei, MD, Windsor Regional Hospital (Windsor, Ontario); Kyong-Soon Lee, MD, MSc, Hospital for Sick Children (Toronto, Ontario); Michael Dunn, MD, Sunnybrook Health Sciences Centre (Toronto, Ontario); Brigitte Lemyre, MD, Children’s Hospital of Eastern Ontario and Ottawa General Hospital (Ottawa, Ontario); Kimberly Dow, MD, Kingston General Hospital (Kingston, Ontario); Ermelinda Pelausa, MD, Jewish General Hospital (Montréal, Québec); Keith Barrington, MBChB, Hôpital Sainte-Justine (Montréal, Québec); Christine Drolet, MD, and Bruno Piedboeuf, MD, Centre Hospitalier Universitaire de Québec (Sainte Foy, Québec); Martine Claveau, MSc, LLM, NNP, and Marc Beltempo, MD, McGill University Health Centre (Montréal, Québec); Valerie Bertelle, MD, and Edith Masse, MD, Centre Hospitalier Universitaire de Sherbrooke (Sherbrooke, Québec); Roderick Canning, MD, Moncton Hospital (Moncton, New Brunswick); Hala Makary, MD, Dr Everett Chalmers Hospital (Fredericton, New Brunswick); Cecil Ojah, MBBS, and Luis Monterrosa, MD, Saint John Regional Hospital (Saint John, New Brunswick); Akhil Deshpandey, MBBS, MRCPI, Janeway Children’s Health and Rehabilitation Centre (St. John’s, Newfoundland); Jehier Afifi, MBBCh, MSc, IWK Health Centre (Halifax, Nova Scotia); Andrzej Kajetanowicz, MD, Cape Breton Regional Hospital (Sydney, Nova Scotia); and Shoo K. Lee, MBBS, PhD (chairman, CNN), Mount Sinai Hospital (Toronto, Ontario).

INN: Brian Reichman, MBChB (director, INN), Sheba Medical Center (Tel Hashomer); Eli Heymann, MD, Assaf Harofeh Medical Center (Tzrifin); Shmuel Zangen, MD, Barzilai Medical Center (Ashkelon); Tatyana Smolkin, MD, Baruch Padeh Medical Center (Poriya); Francis Mimouni, MD, Bikur Cholim Hospital (Jerusalem); David Bader, MD, Bnai Zion Medical Center (Haifa); Avi Rothschild, MD, Carmel Medical Center (Haifa); Zipora Strauss, Chaim Sheba Medical Center (Ramat Gan); Clari Felszer, MD, Emek Medical Center (Afula); Jamalia Jeryes, MD, French Saint Vincent de Paul Hospital (Nazareth); Smadar Even Tov-Friedman, MD, Hadassah University Hospital-Ein Karem (Jerusalem); Benjamin Bar-Oz, MD, Hadassah University Hospital-Har Hazofim (Jerusalem); Michael Feldman, MD, Hillel Yaffe Medical Center (Hadera); Nizar Saad, MD, Holy Family (Italian) Hospital (Nazareth); Orna Flidel-Rimon, MD, Kaplan Medical Center (Rehovot); Meir Weisbrod, MD, Laniado Hospital (Netanya); Daniel Lubin, MD, Mayanei Hayeshua Medical Center (Bnei Brak); Ita Litmanovitz, MD, Meir Medical Center (Kfar Saba); Amir Kugelman, MD, Rambam Medical Center (Haifa); Eric Shinwell, MD, Rivka Ziv Medical Center (Safed); Gil Klinger, MD, Schneider Children’s Medical Center of Israel, Rabin Medical Center (Beilinson Campus) (Petah Tikva); Yousif Nijim, MD, Scottish (EMMS) Hospital (Nazareth); Francis Mimouni, MD, Shaare-Zedek Medical Center (Jerusalem); Agneta Golan, MD, Soroka Medical Center (Beersheba); Dror Mandel, MD, Sourasky Medical Center (Tel Aviv); Vered Fleisher-Sheffer, MD, Western Galilee Medical Center (Nahariya); David Kohelet, MD, Wolfson Medical Center (Holon); and Lev Bakhrakh, MD, Yoseftal Hospital (Eilat).

NRNJ: Satoshi Kusuda, MD (director, NRNJ), Tokyo Women's Medical University (Tokyo); Satoshi Hattori, MD, Sapporo City Hospital (Sapporo, Hokkaido); Shohei Konishi, MD, Kushiro Red Cross Hospital (Kushiro, Hokkaido); Takasuke Amizuka, MD, Aomori Prefectural Central Hospital (Aomori, Aomori); Takeo Kasai, MD, Iwate Medical University (Morioka, Iwate); Ritsuko Takahasi, MD, Sendai Red Cross Hospital (Sendai, Miyagi); Hirokazu Arai, MD, Akita Red Cross Hospital (Akita, Akita); Maki Sato, MD, Fukushima Medical University (Fukushima, Fukushima); Yayoi Miyazono, MD, Tsukuba University (Tsukuba, Ibaraki); Junichi Shimizu, MD, Tsuchiura Kyodo Hospital (Tsuchiura, Ibaraki); Hiroshi Suzumura, MD, Dokkyo Medical University (Shimotsuga, Tochigi); Yumi Kono, MD, Jichi Medical University (Shimotsuke, Tochigi); Takahiro Inoue, MD, Gunma Children’s Medical Center (Shibukawa, Gunma); Hiroshi Miyabayashi, MD, Saitama Children’s Medical Center (Saitama, Saitama); Hisanori Sobajima, Saitama Medical University (Iruma, Saitama); Rika Ishiguro, Kawaguchi Municipal Medical Center (Kawaguchi, Saitama); Hiroyuki Sato, MD, Kameda General Hospital (Chiba, Kamogawa); Satsuki Totsu, MD, Tokyo Women’s Medical University (Shinjuku, Tokyo); Nozomi Ishii, MD, Aiiku Hospital (Minato, Tokyo); Shigeharu Hosono, MD, Nihon University Itabashi Hospital (Itabashi, Tokyo); Mika Shiraishi, MD, Teikyo University (Itabashi, Tokyo); Humihiro Miura, MD, Showa University (Shinagawa, Tokyo); Atsushi Nakao, MD, Japan Red Cross Medical Center (Shibuya, Tokyo); Hitoshi Yoda, MD, Toho University (Ota, Tokyo); Mitsumasa Shimizu, MD, Tokyo Metropolitan Bokuto Hospital (Sumida, Tokyo); Kazuo Seki, MD, Yokohama City University Medical Center (Yokohama, Kanagawa); Yasuhumi Itani, MD, Kanagawa Children’s Medical Center (Yokohama, Kanagawa); Keiji Suzuki, MD, Tokai University (Isehara, Kanagawa); Atsushi Nemoto, MD, Yamanashi Prefectural Central Hospital (Kofu, Yamanashi); Tomohiko Nakamura, MD, Nagano Children’s Hospital (Azumino, Nagano); Masaki Wada, MD, Niigata University (Niigata, Niigata); Yoshihisa Nagayama, MD, Niigata City Hospital (Niigata, Niigata); Osamu Numata, MD, Nagaoka Red Cross Hospital (Nagaoka, Niigata); Takeshi Futatani, MD, Toyama Prefectural Central Hospital (Toyama, Toyama); Yasuhisa Ueno, MD, Ishikawa Prefectural Central Hospital (Kanazawa, Ishikawa); Kazuyuki Iwai, MD, Fukui Prefectural Hospital (Fukui, Fukui); Yoshinori Kono, MD, Gifu Prefectural Medical Center (Gifu, Gifu); Shigeru Ooki, MD, Seirei Hamamatsu General Hospital (Hamamatsu, Shizuoka); Yusuke Nakazawa, MD, Shizuoka Prefectural Children’s Hospital (Shizuoka, Shizuoka); Chizuko Suzuki, MD, Nagoya Red Cross First Hospital (Nagoya, Aichi); Taihei Tanaka, MD, Nagoya Red Cross Second Hospital (Nagoya, Aichi); Motoki Bonno, MD, Mie Central Medical Center (Tsu, Mie); Kenji Nakamura, MD, Ohtsu Red Cross Hospital (Otsu, Shiga); Minako Kihara, MD, Kyoto Red Cross First Hospital (Kyoto, Kyoto); Hiroyuki Sano, MD, Yodogawa Christian Hospital (Osaka, Osaka); Atsushi Shiraishi, MD, Osaka Medical Center and Research Institute for Maternal and Child Health (Osaka, Izumi); Atsushi Ohashi, MD, Kansai Medical University Hirakata Hospital (Hirakata, Osaka); Hiroyuki Ichiba, MD, Osaka City General Hospital (Osaka, Osaka); Kiyoaki Sumi, MD, Aizenbashi Hospital (Osaka, Osaka); Seiji Yoshimoto, MD, Kobe Children’s Hospital (Kobe, Hyogo); Yukihiro Takahashi, MD, Nara Medical University (Nara, Nara); Takahiro Okutani, MD, Wakayama Medical University (Wakayama, Wakayama); Masumi Miura, MD, Tottori University (Yonago, Tottori); Fumihide Kato, MD, Shimane Prefectural Central Hospital (Izumo, Shimane); Shinichi Watabe, MD, Kurashiki Central Hospital (Kurashiki, Okayama); Misao Kageyama, MD, Okayama Medical Center (Okayama, Okayama); Rie Fukuhara, MD, Hiroshima Prefectural Hospital (Hiroshima, Hiroshima); Michiko Hayashitani, MD, Hiroshima City Hospital (Hiroshima, Hiroshima); Keiko Hasegawa, MD, Yamaguchi Prefectural Medical Center (Hofu, Yamaguchi); Kosuke Koyano, MD, Kagawa University (Kita, Kagawa); Shoko Kobayashi, MD, Shikoku Medical Center for Children and Adults (Zentsuji, Kagawa); Shinosuke Akiyoshi, MD, Ehime Prefectural Central Hospital (Matsuyama, Ehime); Yusei Nakata, MD, Kochi Health Sciences Center (Kochi, Kochi); Takeshi Kanda, MD, National Kyushu Medical Center (Fukuoka, Fukuoka); Hisano Tadashi, MD, St Mary’s Hospital (Kurume, Fukuoka); Hiroshi Kanda, MD, Kurume University (Kurume, Fukuoka); Masaki Nakamura, Fukuoka University (Fukuoka, Fukuoka); Naoko Matsumoto, MD, Kitakyushu City Medical Center (Kitakyushu, Fukuoka); Masayuki Ochiai, MD, Kyushu University (Fukuoka, Fukuoka); Mikihiro Aoki, MD, Nagasaki Medical Center (Omura, Nagasaki); Akihiko Kawase, MD, Kumamoto City Hospital (Kumamoto, Kumamoto); Koichi Iida, MD, Oita Prefectural Center Hospital (Oita, Oita); Chie Ishihara, MD, Kagoshima City Hospital (Kagoshima, Kagoshima); and Moriyasu Kohama, MD, Okinawa Prefectural Chubu Hospital (Okinawa, Okinawa).

SEN1500: Maximo Vento, MD, PhD (director, SEN1500), Health Research Institute La Fe (valencia, Valencia); Mª José Fernández Seara, MD, and José Mª Fraga Bermúdez, MD, Hospital Clinico Universitario Santiago (A Coruña, Galicia); Andrés Martínez Gutiérrez, MD, Complejo Hospitalario De Albacete (Albacete, Albacete); María Mercedes Martínez Ayúcar, MD, Hospital de Txagorritxu (Vitoria-Gasteiz, Araba); Carolina Vizcaíno Díaz, MD, and José Luis Quiles Durá, MD, Hospital General Universitario de Elche (Alicante, Alicante); María González Santacruz, MD, and Mª Anne Feret Siguile, MD, Hospital General Universitario de Alicante (Alicante, Alicante); Adela Rodríguez Fernández, MD, Hospital de Cabueñes (Gijon, Asturias); Belén Fernández Colomer, MD, and Enrique García López, MD, Hospital Universitario Central de Asturias (Oviedo, Asturias); Josep Figuera Aloy, MD, and Francesc Botet Mussons, MD, Hospital Clínic de Barcelona (Barcelona, Catalonia); Israel Anquela Sanz, MD, Hospitalario De Granollers (Granollers, Barcelona); Gemma Ginovart Galiana, MD, and Elisenda Moliner Calderon, MD, Hospital De Sant Pau (Barcelona, Catalonia); Antonio Natal Pujol, MD, Hospital Universitari Germans Trias i Pujol (Badalona, Barcelona); Alicia Mirada Vives, MD, Hospital Universitari Mutua De Terrassa (Barcelona, Catalonia); Martín Iriondo Sanz, MD, Hospital San Juan De Deu (Barcelona, Catalonia); Roser Porta, MD, and Eva Capdevila Cogul, MD, I. Dexeus (Barcelona, Catalonia); Laura Castells Vilella, MD, Hospital General de Cataluñá (Barcelona, Catalonia); Bruno Alonso Álvarez, MD, and José María Montero Macarro, MD, Hospital General Yagüe (Burgos, Castile); Ana R. Barrio Sacristán, MD, and Mª Jesús López Cuesta, MD, H. San Pedro de Alcántara (Caceres, Caceres); Ortiz Tardío, MD, and Eugenia Valls Sánchez Puerta, MD, Hospital Jerez (Cádiz, Cádiz); Isabel Benavente Fernández, MD, and Juan Mena Romero, MD, Hospital Universitario Puerta Del Mar (Cádiz, Cádiz); María Dolores Martinez Gimenez, MD, Hospital General Universitario de Ciudad Real (Ciudad Real, Castile); Ramón Aguilera Olmos, MD, and Ricardo Tosca Segura, MD, Hospital General de Castelló (Castelló, Castelló); Juana Mª Guzmán Cabañas, MD, and Mª Dolores Huertas μñoz, MD, Hospital Universitario Reina Sofía (Cordoba, Andalusia); Alberto Trujillo, MD, Hospital Universitari de Josep Trueta (Girona, Catalonia); Luis Fidel Moltó Ripoll, MD, and José Antonio Hurtado Suazo, MD, Hospital Universitario Virgen De Las Nieves (Granada, Granada); Ana Elena Aldea Romero, MD, and María Pangua Gómez, MD, Hospital Universitario de Guadalajara (Guadalajara, Castile); Luis Paisán Grisolía, MD, Hospital Donostia (Donostia, Gipuzkoa); Ana Isabel Garrido Ocana, MD, and Eduardo Garcia Soblechero, MD, Hospital Juan Ramón Jiménez (Huelva, Huelva); Mª Yolanda Ruiz del Prado, MD, and Inés Esteba Díez, MD, Hospital San Pedro (Logroño, La Rioja); Gema E. González-Luis, MD, and Fermín García-μñoz Rodrigo, MD, Hospital Universitario De Canarias (San Cristóbal de La Laguna, Santa Cruz de Tenerife); Emilio Álvaro Iglesias, MD, and Fernando Fernandez Calvo, MD, Hospital Universitario de León (León, León); Eduard Solé Mir, MD, and Jordi Garcia Martí, MD, University Hospital Arnau De Vilanova (Lleida, Catalonia); Roberto Ortiz Movilla, MD, and Lucía Cabanillas Vilaplana, MD, Hospital Universitario de Getafe (Madrid, Madrid); Marta García San Miguel, MD, Hospital Universitario Montepríncipe (Madrid, Madrid); Isabel Llana Martín, MD, and María Fernández Díaz, MD, Hospital Universiatrio Torrelodonesm (Madrid, Madrid); Jesús Pérez Rodríguez, MD, and Sofía Salas, MD, Hospital Universitario La Paz (Madrid, Madrid); Carmen μñoz Labian, MD, and Carmen González Armengod, MD, Hospital Universitario Puerta De Hierro (Majadahonda, Madrid); Laura Domingo Comeche, MD, Hospital Universitario de Fuenlabrada (Feunlabrada, Madrid); Tomás Sánchez Tamayo, MD, and Manuel García del Río, MD, Hospital Carlos Haya (Málaga, Málaga); José Ángel Alonso Gallego, MD, and José María Lloreda Garcia, MD, Hospital Santa María De Rosell (Caragena, Murcia); Javier Vilas González, MD, Complexo Hospitalario Pontevedra (Pontevedra, Pontevedra); Ocampo, MD, and Nieves Balado Insunza, MD, Hospital Xeral (Vigo, Pontevedra); Pilar García González, MD, Hospital Universitario de Salamanca (Salamanca, Castile); Mercedes Granero Asencio, MD, and Antonia López Sanz, MD, Hospital Virgen De La Macarena (Sevilla, Seville); Carmen Macías Díaz, MD, and Araceli Ferrari Cortés, MD, Hospital Universitario Virgen Del Rocío (Sevilla, Seville); Pedro Amadeo Fuster Jorge, MD, Hospital Universitario de Canarias (San Cristóbal de La Laguna, Santa Cruz de Tenerife); Santiago López Mendoza, MD, and Sabina Romero Ramírez, MD, Hospital Universitario Nuestra Señora De Candelaria (Santa Cruz de Tenerife, Santa Cruz de Tenerife); Mª del Mar Albújar Font, MD, Hospital Universitari Joan XXIII (Tarragona, Tarragona); Alicia de Ureta Huertas, MD, and Antonio Arroyos Plana, MD, Hospital Virgen De La Salud (Toledo, Toledo); Javier Estañ Capell, MD, Hospital Clinico Universitario De Valencia (Valencia, Valencia); Vicente Roqués, MD, and F Morcillo, MD, Hospital Universitari La Fe (Valencia, Valencia); Sara Marín, MD, and María Fernanda Omaña, MD, Hospital Universiatario Río Hortega (Valladolid, Castile and Leon); and Gabriel Saitua Iturriaga, MD, Hospital de Basurto (Bilbao, Vizcaya, Bizkaia).

SNQ: Jiri Kofron, MD, Södra Älvsborgs Sjukhus (Borås); Katarina Strand Brodd, MD, Mälarsjukhuset (Eskilstuna); Andreas Odlind, MD, Falu Lasarett (Falun); Lars Alberg, MD, Gällivare Sjukhus (Gällivare); Sofia Arwehed, MD, Gävle Sjukhus (Gävle); Eva Engström, MD, SU/Östra (Göteborg); Anna Kasemo, MD, Länssjukhuset (Halmstad); Charlotte Ekelund, MD, Helsingborgs Lasarett (Helsingborg); Lars Åhman, MD, Hudiksvalls Sjukhus (Hudiksvall); Fredrik Ingemarsson, MD, Länssjukhuset Ryhov (Jönköping); Laura Österdahl, MD, Länssjukhuset (Kalmar); Pernilla Thurn, MD, Blekingesjukhuset (Karlskrona); Eva Albinsson, MD, Centralsjukhuset (Karlstad); Bo Selander, MD, Centralsjukhuset (Kristianstad); Fredrik Lundberg, MD, Universitetssjukhuset (Linköping); Ingela Heimdahl, MD, Sunderby sjukhus (Luleå); Ola Hafström, MD, Skånes Universitetssjukhus (Malmö/Lund); Erik Wejryd, MD, Vrinnevisjukhuset (Norrköping); Johanna Kuusima-Löfbom, MD, Skellefteå Lasarett (Skellefteå); Ellen-Elisabeth Lund, MD, Kärnsjukhuset Skaraborg (Skövde); Annelie Thorén, MD, Sollefteå Sjukhus (Sollefteå); Boubou Hallberg, MD, Karolinska Sjukhuset (Stockholm); Eva Berggren Broström, MD, Södersjuhuset, (Stockholm); Torbjörn Hertzberg, MD, Sophiahemmet (Stockholm); Björn Stjernstedt, MD, Länssjukhuset (Sundsvall); Johan Robinson, MD, Norra Älvsborgs Länssjukhus (Trollhättan); Aijaz Farooqi, MD, Norrlands Universitetssjukhus (Umeå); Erik Normann, MD, Akademiska Barnsjukhuset (Uppsala); Magnus Fredriksson, MD, Visby Lasarett (Visby); Anders Palm, MD, Västerviks Sjukhus (Västervik); Åsa Hedblom, MD, Centrallasarettet (Västerås); Kenneth Sjöberg, MD, Centrallasarettet (Växjö); Leif Thorbjörnsson, MD, Lasarettet (Ystad); Andreas Ohlin, MD, Universitetssjukhuset (Örebro); Rein Florell, MD, Örnsköldsviks Sjukhus (Örnsköldsvik); and Agneta Smedsaas-Löfvenberg, MD, Östersunds Sjukhus (Östersund).

SwissNeoNet: Mark Adams, MsC (coordinator, SwissNeoNet); Philipp Meyer, MD, and Claudia Anderegg, MD, Cantonal Hospital, Children’s Clinic (Aarau); Sven Schulzke, MD, University Children’s Hospital (Basel); Mathias Nelle, MD, University Hospital (Berne); Bendicht Wagner, MD, University Hospital (Berne); Walter Bär, MD, Children’s Hospital (Chur); Grégoire Kaczala, MD, Cantonal Hospital (Fribourg); Riccardo E. Pfister, MD, Geneva University Hospital (Geneva); Jean-François Tolsa, MD, and Matthias Roth, MD, University Hospital (CHUV) (Lausanne); Thomas M. Berger, MD, Children’s Hospital (Lucerne); Bernhard Laubscher, MD, Cantonal Hospital (Neuchatel); Andreas Malzacher, MD, Cantonal Hospital (St. Gallen); John P. Micallef, MD, Children’s Hospital (St. Gallen); Lukas Hegi, MD, Cantonal Hospital (Winterthur); Dirk Bassler, MD, and Romaine Arlettaz, MD, University Hospital Zurich (Zurich); and Vera Bernet, MD, University Children’s Hospital (Zurich).

UKNC: Santanu Bag, MBChB, Bedford Hospital (Bedford, Bedfordshire); Jonathan Kefas, MBChB, Lister Hospital (Stevenage, Hertfordshire); Oliver Rackham, MBChB, Arrowe Park Hospital (Wirral, Merseyside); Arumugavelu Thirumurgan, MBChB, Leighton Hospital (Crewe, Cheshire); Bill Yoxall, MBChB, Liverpool Women’s Hospital (Liverpool, Merseyside); Tim McBride, MBChB, Ormskirk District General Hospital (Ormskirk, Lancashire); Delyth Webb, MBChB, Warrington Hospital (Warrington, Cheshire); Laweh Amegavie, MBChB, Whiston Hospital (Prescot, Merseyside); Ahmed Hassan, MBChB, Broomfield Hospital (Chelmsford, Essex); Priyadarshan Ambadkar, MBChB, James Paget Hospital (Gorleston, Norfolk); Mark Dyke, MBChB, Norfolk and Norwich University Hospital (Norwich, Norfolk); Seif Babiker, MBChB, Peterborough City Hospital (Peterborough, Cambridgeshire); Susan Rubin, MBChB, Queen Elizabeth Hospital, King’s Lynn (Birmingham, West Midlands); Amanda Ogilvy-Stuart, MBChB, Rosie Maternity Hospital (Addenbrookes, Cambridge, Cambridgeshire); Nagesh Panasa, MBChB, North Manchester General Hospital (Manchester, Greater Manchester); Paul Settle, MBChB, Royal Bolton Hospital (Bolton, Lancashire); Jonathan Moise, MBChB, Royal Oldham Hospital (Manchester, Greater Manchester); Ngozi Edi-Osagie, MBChB, St Mary’s Hospital (Manchester, Greater Manchester); Christos Zipitis, MBChB, The Robert Albert Edward Infirmary (Wrightington, Greater Manchester); Carrie Heal, MBChB, Stepping Hill Hospital (Stockport, Cheshire); Jacqeline Birch, MBChB, Tameside General Hospital (Ashton-under-Lyne, Lancashire); Abdul Hasib, MBChB, Darent Valley Hospital (Dartford, Kent); Aung Soe, MBChB, Medway Maritime Hospital (Gillingham, Kent); Niraj Kumar, MBChB, Queen Elizabeth The Queen Mother Hospital (Margate, Kent); Hamudi Kisat, MBChB, Tunbridge Wells Hospital (Tunbridge Wells, Kent); Vimal Vasu, MBChB, William Harvey Hospital (Ashford, Kent); Meera Lama, MBChB, Lancashire Women & Newborn Centre (Burnley, Lancashire); Richa Gupta, MBChB, Royal Preston Hospital (Preston, Lancashire); Chris Rawlingson, MBChB, Blackpool Victoria Hospital (Blackpool, Lancashire); Tim Wickham, MBChB, Barnet Hospital (Barnet, Hertfordshire); Karin Schwarz, MBChB, Chase Farm Hospital (Enfield, Middlesex); Van Sommen, MBChB, The Royal Free Hospital (Hampstead, London); Sara Watkin, MBChB, University College Hospital (Fitzrovia, London); Aashish Gupta, MBChB, Basildon Hospital (Basildon, Essex); Narendra Aladangady, MBChB, Homerton Hospital (Hackney, London); Imdad Ali, MBChB, Newham General Hospital (Newham, London); Lesley Alsford, MBChB, North Middlesex University Hospital (Edmonton, London); Khalid Mannan, MBChB, Queen’s Hospital (Romford, Essex); Ebel Rainer, MBChB, The Royal London Hospital (Whitechapel, London); Nicholas Wilson, MBChB, Whipps Cross University Hospital (Whipps Cross, London); Mark Thomas, MBChB, Chelsea and Westminster Hospital (Chelsea, London); Ramnik Mathur, MBChB, Ealing Hospital (Southall, London); Michele Cruwys, MBChB, Hillingdon Hospital (Hillingdon, London); Sunit Godambe, MBChB, Queen Charlotte’s Hospital (East Acton, London); Sunit Godambe, MBChB, St Mary’s Hospital (Westminster, London); Timothy Watts, MBChB, Guy’s and St Thomas’ Hospital (Lambeth, London); Jauro Kuna, MBChB, University Hospital Lewisham (Lewisham, London); John Chang, MBChB, Croydon University Hospital (Croydon, Surrey); Jon Filkin, MBChB, Kingston Hospital (Kingston, London); Charlotte Huddy, MBChB, St George’s Hospital (Wandsworth, London); Ruth Shephard, MBChB, St. Helier Hospital (Merton, London); Krzystof Zieba, MBChB, Northwick Park Hospital (Brent, London); Patti Rao, MBChB, Kettering General Hospital (Kettering, Northhamptonshire); Andrew Currie, MBChB, Leicester General Hospital (Leicester, Leicestershire); Andrew Currie, MBChB, Leicester Royal Infirmary (Leicester, Leicestershire); Azhar Manzoor, MBChB, Queen’s Hospital, Burton-on-Trent (Burton-on-Trent, Staffordshire); Munir Ahmed, MBChB, Alexandra Hospital (Redditch, Worcestershire); Phil Simmons, MBChB, Birmingham Heartlands Hospital (Birmingham, West Midlands); Julie Nycyk, MBChB, City Hospital (Birmingham, West Midlands); Phil Simmons, MBChB, Good Hope Hospital (Birmingham, West Midlands); Andrew Gallagher, MBChB, Worcestershire Royal Hospital (Worcester, Worcestershire); Chrisantha Halahakoon, MBChB, New Cross Hospital (Wolverhampton, West Midlands); Sanjeev Deshpande, MBChB, Royal Shrewsbury Hospital (Shrewsbury, Shropshire); Anand Mohite, MBChB, Russells Hall Hospital (Dudley, West Midlands); Kate Palmer, MBChB, University Hospital of North Staffordshire (Hartshill, Staffordshire); Alan Gibson, MBChB, Jessop Hospital (Sheffield, South Yorkshire); Mehdi Garbash, MBChB, Darlington Memorial Hospital (Darlington, County Durham); Mithilesh Lal, MBChB, James Cook University Hospital (Middlesborough, North Yorkshire); Majd Abu-Harb, MBChB, Sunderland Royal Hospital (Sunderland, Tyne and Wear); Mehdi Garbash, MBChB, University Hospital of North Durham (Durham, Durham); Róisín McKeon-Carter, MBChB, Derriford Hospital (Plymouth, Devon); Michael Selter, MBChB, North Devon District Hospital (Barnstaple, Devon); Paul Munyard, MBChB, Royal Cornwall Hospital (Truro, Cornwall); Vaughan Lewis, MBChB, Royal Devon and Exeter Hospital (Exeter, Devon); Mala Raman, MBChB, Torbay Hospital (Torquay, Devon); Graham Whincup, MBChB, Conquest Hospital (St. Leonards-on-Sea, East Sussex); Abdus Mallik, MBChB, Frimley Park Hospital (Frimley, Surrey); Philip Amess, MBChB, Princess Royal Hospital (Telford, Shropshire); Charles Godden, MBChB, Royal Surrey County Hospital (Guildford, Surrey); Philip Amess, MBChB, Royal Sussex County Hospital (Brighton, East Sussex); Peter Reynolds, MBChB, St Peter’s Hospital (Chertsey, Surrey); Indranil Misra, MBChB, Milton Keynes Foundation Trust Hospital (Milton Keynes, Buckinghamshire); Naveen Shettihalli, MBChB, Oxford University Hospitals, Horton Hospital (Oxford, Oxfordshire); Peter De Halpert, MBChB, Royal Berkshire Hospital (Reading, Berkshire); Sanjay Salgia, MBChB, Stoke Mandeville Hospital (Aylesbury, Buckinghamshire); Rekha Sanghavi, MBChB, Wexham Park Hospital (Slough, Berkshire); Ruth Wigfield, MBChB, Basingstoke and North Hampshire Hospital (Basingstoke, Hampshire); Abby Deketelaere, MBChB, Dorset County Hospital (Dorchester, Dorset); Minesh Khashu, MBChB, Poole Hospital NHS Foundation Trust (Poole, Dorset); Michael Hall, MBChB, Princess Anne Hospital (Southampton, Hampshire); Charlotte Groves, MBChB, Queen Alexandra Hospital (Portsmouth, Hampshire); Nick Brown, MBChB, Salisbury District Hospital (Salisbury, Wiltshire); Nick Brennan, MBChB, St Richard’s Hospital (Chichester, West Sussex); Katia Vamvakiti, MBChB, Worthing Hospital (Worthing, West Sussex); Mal Ratnayaka, MBChB, Royal Derby Hospital (Derby, Derbyshire); Simon Pirie, MBChB, Gloucestershire Royal Hospital (Gloucester, Glourcestershire); Stephen Jones, MBChB, Royal United Hospital (Avon, Somerset); Paul Mannix, MBChB, Southmead Hospital (Westbury-on-Trym, Bristol); David Harding, MBChB, St Michael’s Hospital (Bristol, Bristol); Megan Eaton, MBChB, Yeovil District Hospital (Yeovil, Somerset); Karin Schwarz, MBChB, Calderdale Royal Hospital (Halifax, West Yorkshire); David Gibson, MBChB, Dewsbury and District Hospital (Dewsbury, West Yorkshire); Lawrence Miall, MBChB, Leeds Neonatal Service (Leeds, Yorkshire); and David Gibson, MBChB, Pinderfields General Hospital (Wakefield, West Yorkshire).

FinMBR: Sture Andersson, MD, Helsinki University Hospital (Helsinki); Liisa Lehtonen, MD, Turku University Hospital (Turku); Outi Tammela, MD, Tampere University Hospital (Tampere); Ulla Sankilampi, MD, Kuopio University Hospital (Kuopio); and Timo Saarela, MD, Oulu University Hospital (Oulu).

TuscanNN: Carlo Dani, MD, Careggi University Hospital (Florence); Patrizio Fiorini, MD, Anna Meyer Children’s University Hospital (Florence); Antonio Boldrini, MD, University Hospital of Pisa (Pisa); and Barbara Tomasini, MD, University Hospital of Siena (Siena).

1
Liu
L
,
Oza
S
,
Hogan
D
, et al
.
Global, regional, and national causes of child mortality in 2000-13, with projections to inform post-2015 priorities: an updated systematic analysis.
Lancet
.
2015
;
385
(
9966
):
430
440
[PubMed]
2
Stoll
BJ
,
Hansen
NI
,
Bell
EF
, et al;
Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network
.
Trends in care practices, morbidity, and mortality of extremely preterm neonates, 1993-2012.
JAMA
.
2015
;
314
(
10
):
1039
1051
[PubMed]
3
Shah
PS
,
Sankaran
K
,
Aziz
K
, et al;
Canadian Neonatal Network
.
Outcomes of preterm infants <29 weeks gestation over 10-year period in Canada: a cause for concern?
J Perinatol
.
2012
;
32
(
2
):
132
138
[PubMed]
4
Berger
TM
,
Steurer
MA
,
Woerner
A
,
Meyer-Schiffer
P
,
Adams
M
;
Swiss Neonatal Network
.
Trends and centre-to-centre variability in survival rates of very preterm infants (<32 weeks) over a 10-year-period in Switzerland.
Arch Dis Child Fetal Neonatal Ed
.
2012
;
97
(
5
):
F323
F328
[PubMed]
5
Ancel
P-Y
,
Goffinet
F
,
Kuhn
P
, et al;
EPIPAGE-2 Writing Group
.
Survival and morbidity of preterm children born at 22 through 34 weeks’ gestation in France in 2011: results of the EPIPAGE-2 cohort study [published correction appears in JAMA Pediatr. 2015;169(4):323].
JAMA Pediatr
.
2015
;
169
(
3
):
230
238
[PubMed]
6
Tommiska
V
,
Heinonen
K
,
Lehtonen
L
, et al
.
No improvement in outcome of nationwide extremely low birth weight infant populations between 1996-1997 and 1999-2000.
Pediatrics
.
2007
;
119
(
1
):
29
36
[PubMed]
7
Serenius
F
,
Sjörs
G
,
Blennow
M
, et al;
EXPRESS Study Group
.
EXPRESS study shows significant regional differences in 1-year outcome of extremely preterm infants in Sweden.
Acta Paediatr
.
2014
;
103
(
1
):
27
37
[PubMed]
8
Costeloe
KL
,
Hennessy
EM
,
Haider
S
,
Stacey
F
,
Marlow
N
,
Draper
ES
.
Short term outcomes after extreme preterm birth in England: comparison of two birth cohorts in 1995 and 2006 (the EPICure studies).
BMJ
.
2012
;
345
:
e7976
[PubMed]
9
Numerato
D
,
Fattore
G
,
Tediosi
F
, et al
.
Mortality and length of stay of very low birth weight and very preterm infants: a EuroHOPE study.
PLoS One
.
2015
;
10
(
6
):
e0131685
[PubMed]
10
García-Muñoz Rodrigo
F
,
Díez Recinos
AL
,
García-Alix Pérez
A
,
Figueras Aloy
J
,
Vento Torres
M
.
Changes in perinatal care and outcomes in newborns at the limit of viability in Spain: the EPI-SEN study.
Neonatology
.
2015
;
107
(
2
):
120
129
[PubMed]
11
Grisaru-Granovsky
S
,
Reichman
B
,
Lerner-Geva
L
, et al;
Israel Neonatal Network
.
Population-based trends in mortality and neonatal morbidities among singleton, very preterm, very low birth weight infants over 16 years.
Early Hum Dev
.
2014
;
90
(
12
):
821
827
[PubMed]
12
Fellman
V
,
Hellström-Westas
L
,
Norman
M
, et al;
EXPRESS Group
.
One-year survival of extremely preterm infants after active perinatal care in Sweden.
JAMA
.
2009
;
301
(
21
):
2225
2233
[PubMed]
13
Zeitlin
J
,
Mortensen
L
,
Cuttini
M
, et al;
Euro-Peristat Scientific Committee
.
Declines in stillbirth and neonatal mortality rates in Europe between 2004 and 2010: results from the Euro-Peristat project.
J Epidemiol Community Health
.
2016
;
70
(
6
):
609
615
[PubMed]
14
Shah
PS
,
Lee
SK
,
Lui
K
, et al;
International Network for Evaluating Outcomes of Neonates (iNeo)
.
The International Network for Evaluating Outcomes of very low birth weight, very preterm neonates (iNeo): a protocol for collaborative comparisons of international health services for quality improvement in neonatal care.
BMC Pediatr
.
2014
;
14
:
110
[PubMed]
15
Sankilampi
U
,
Hannila
ML
,
Saari
A
,
Gissler
M
,
Dunkel
L
.
New population-based references for birth weight, length, and head circumference in singletons and twins from 23 to 43 gestation weeks.
Ann Med
.
2013
;
45
(
5–6
):
446
454
[PubMed]
16
Martin
LJ
,
Sjörs
G
,
Reichman
B
, et al;
International Network for Evaluating Outcomes (iNeo) of Neonates Investigators
.
Country-specific vs. common birthweight-for-gestational age references to identify small for gestational age infants born at 24-28 weeks: an international study.
Paediatr Perinat Epidemiol
.
2016
;
30
(
5
):
450
461
[PubMed]
17
Bertino
E
,
Spada
E
,
Occhi
L
, et al
.
Neonatal anthropometric charts: the Italian neonatal study compared with other European studies.
J Pediatr Gastroenterol Nutr
.
2010
;
51
(
3
):
353
361
[PubMed]
18
Shah
PS
,
Lui
K
,
Sjörs
G
, et al;
International Network for Evaluating Outcomes (iNeo) of Neonates
.
Neonatal outcomes of very low birth weight and very preterm neonates: an international comparison.
J Pediatr
.
2016
;
177
:
144
152.e6
[PubMed]
19
Draper
ES
,
Manktelow
BN
,
Cuttini
M
, et al;
EPICE Cohort
.
Variability in very preterm stillbirth and in-hospital mortality across Europe.
Pediatrics
.
2017
;
139
(
4
):
e20161990
[PubMed]
20
Phibbs
CS
,
Baker
LC
,
Caughey
AB
,
Danielsen
B
,
Schmitt
SK
,
Phibbs
RH
.
Level and volume of neonatal intensive care and mortality in very-low-birth-weight infants.
N Engl J Med
.
2007
;
356
(
21
):
2165
2175
[PubMed]
21
Synnes
AR
,
Macnab
YC
,
Qiu
Z
, et al;
Canadian Neonatal Network
.
Neonatal intensive care unit characteristics affect the incidence of severe intraventricular hemorrhage.
Med Care
.
2006
;
44
(
8
):
754
759
[PubMed]
22
Rysavy
MA
,
Li
L
,
Bell
EF
, et al;
Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network
.
Between-hospital variation in treatment and outcomes in extremely preterm infants.
N Engl J Med
.
2015
;
372
(
19
):
1801
1811
[PubMed]
23
Fischer
N
,
Steurer
MA
,
Adams
M
,
Berger
TM
;
Swiss Neonatal Network
.
Survival rates of extremely preterm infants (gestational age <26 weeks) in Switzerland: impact of the Swiss guidelines for the care of infants born at the limit of viability.
Arch Dis Child Fetal Neonatal Ed
.
2009
;
94
(
6
):
F407
F413
[PubMed]
24
Zegers
MJ
,
Hukkelhoven
CWPM
,
Uiterwaal
CSPM
,
Kollée
LAA
,
Groenendaal
F
.
Changing Dutch approach and trends in short-term outcome of periviable preterms.
Arch Dis Child Fetal Neonatal Ed
.
2016
;
101
(
5
):
F391
F396
[PubMed]
25
Ishii
N
,
Kono
Y
,
Yonemoto
N
,
Kusuda
S
,
Fujimura
M
;
Neonatal Research Network, Japan
.
Outcomes of infants born at 22 and 23 weeks’ gestation.
Pediatrics
.
2013
;
132
(
1
):
62
71
[PubMed]
26
Patel
RM
,
Kandefer
S
,
Walsh
MC
, et al;
Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network
.
Causes and timing of death in extremely premature infants from 2000 through 2011.
N Engl J Med
.
2015
;
372
(
4
):
331
340
[PubMed]
27
Mohamed
MA
,
Nada
A
,
Aly
H
.
Day-by-day postnatal survival in very low birth weight infants.
Pediatrics
.
2010
;
126
(
2
). Available at: www.pediatrics.org/cgi/content/full/126/2/e360
[PubMed]
28
Corchia
C
,
Ferrante
P
,
Da Frè
M
, et al
.
Cause-specific mortality of very preterm infants and antenatal events.
J Pediatr
.
2013
;
162
(
6
):
1125
1132, 1132.e1–e4
[PubMed]
29
Papiernik
E
,
Zeitlin
J
,
Delmas
D
, et al;
MOSAIC Research Group
.
Termination of pregnancy among very preterm births and its impact on very preterm mortality: results from ten European population-based cohorts in the MOSAIC study.
BJOG
.
2008
;
115
(
3
):
361
368
[PubMed]
30
Eventov-Friedman
S
,
Kanevsky
H
,
Bar-Oz
B
.
Neonatal end-of-life care: a single-center NICU experience in Israel over a decade.
Pediatrics
.
2013
;
131
(
6
). Available at: www.pediatrics.org/cgi/content/full/131/6/e1889
[PubMed]
31
Rautava
L
,
Lehtonen
L
,
Peltola
M
, et al;
PERFECT Preterm Infant Study Group
.
The effect of birth in secondary- or tertiary-level hospitals in Finland on mortality in very preterm infants: a birth-register study.
Pediatrics
.
2007
;
119
(
1
). Available at: www.pediatrics.org/cgi/content/full/119/1/e257
[PubMed]
32
Synnes
A
,
Luu
TM
,
Moddemann
D
, et al;
Canadian Neonatal Network and the Canadian Neonatal Follow-Up Network
.
Determinants of developmental outcomes in a very preterm Canadian cohort.
Arch Dis Child Fetal Neonatal Ed
.
2017
;
102
(
3
):
F235
F234
[PubMed]

Competing Interests

POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.

FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.

Supplementary data