In a recently release study in Pediatrics (10.1542/peds.2020-0610), Dr. Minna Honkila and colleagues from Norway examine the interesting question of whether childhood urinary tract infections are associated with long term damage to the kidneys, as assessed by pregnancy related outcomes including essential and gestational hypertension and preeclampsia. This population based study took place in just the right place, because Norway’s social and health services lend themselves to comprehensive tracking over time. The authors were able to identify their initial cohort using a registry of all children who had undergone renal or urinary tract imaging due to urinary tract infection (UTI) in childhood at the Oulu University Hospital, Finland (1981-1991). Inclusions and exclusions are carefully described. Next, using another general registry, that of all mothers in the city of Oulu giving birth at the Oulu University Hospital, the authors identified those women who had given birth who were affected, and additionally selected two controls (who had not had imaging for childhood UTI) for each affected woman. Since public maternity clinics in Finland are used by all women, the saga of data availability continues, and the authors were able to compile results from antenatal appointments on almost all in their cohort.
From an initial group of 1,175 girls with childhood UTI, of whom 342 (29%) had given birth at the time of the study, 260 mothers of the original group of girls could be included in the study, as well as 500 controls matched for delivery date and age. We learn first the details of each mother’s medical course with respect to infections and imaging as a girl. Then the authors present the pregnancy details of these now grown women, as compared to the matched controls, with respect to both renal measures such as blood pressure and proteinuria, and to pregnancy outcomes such as preterm versus term delivery.
Kudos to the authors for this thorough and thoughtful study, and kudos to our own Editors for publishing this study: the authors found that childhood UTI did not appear to be associated with increased risk for any adverse or negative pregnancy outcomes. “Negative studies,” i.e. ones which do not identify a new and exciting association (or any association at all) risk not being published since they may be less attractive to readers and less newsworthy. But if well done and valid like this one, such studies are scientifically important and readers deserve to hear all the truths that investigators find, not just the positive ones. This is a very reassuring “negative” study, and I encourage you to read it for its details and careful methodology. It will give you good and encouraging information to share with your families.