In a recently released article in Pediatrics, Alice Guan and colleagues examine whether changes to the special supplemental nutrition program for Women, Infants and Children (WIC) food package made in 2009 have impacted early child developmental and growth outcomes (10.1542/peds.2020-1853). Some of the key changes to the WIC food package in October 2009 were the addition of more vegetables, fruits, and whole grains, a change to lower fat milk and a 50% decrease in the juice allotment. While prior literature documented that these changes improved availability of healthy foods, maternal and child diet quality, breastfeeding rates, and perinatal and birth outcomes (see references in the article), no studies had yet asked whether children of women receiving the revised food package during pregnancy had improved socioemotional, cognitive or growth outcomes.
This ambitious study used a “quasi-experimental” design, in which over 1,500 women self-reported receipt (or non-receipt) of the WIC food package during pregnancy as part of a longitudinal cohort study, Conditions Affecting Neurocognitive Development and Learning in Early Childhood, conducted in Memphis, TN. The timeline for the study, 2006-2011, fortuitously “crossed” from pre-2009 to after the food package revision. Major outcomes included child growth at ages 1, 2 and 4-6 years, and socioemotional and cognitive development, measured using validated scales, including the Brief Infant Toddler Social Emotional Assessment, the Bayley Scales of Infant Development and the Stanford-Binet Intelligence Scales. While data on receipt of WIC postpartum was unfortunately not available, the authors were able to compare children of women who received the WIC food package during pregnancy before and after the food package revision. They conducted a “difference-in-differences” analysis, which as explained, allowed them to essentially account for secular (time-based) trends and include the assumption that WIC food package changes were not impacted by participant characteristics.
I don’t want to spoil your enjoyment in reading this article, so please read about the growth outcomes by following a link to the article; however, it’s difficult not to share that at age 2 years, those children whose expectant mothers had received the 2009 revised food package, versus the pre-2009 package, had a 4.3 point score advantage (95% CI: 1.1, 7.57) on the Bayley cognitive composite score. This statistically significant difference is also clinically meaningful: it represents one third of a standard deviation, and aligns with previous results comparing children whose families did versus did not participate in WIC. The authors postulate that improved maternal nutrition during pregnancy could lead to a process called “fetal programming,” in which epigenetic changes to the fetal genome cause lasting physiologic changes in the fetus.
Now that we are aware of this key benefit, the biggest question in my mind is how we as pediatricians can better support mothers to receive WIC, if eligible, during their pregnancies? While 4 in 10 expectant women (39.6%) in the United States did receive WIC benefits1, reports of the proportion of women eligible but not receiving WIC during pregnancy range from 17-29.1% and vary by state and demographic descriptors2,3. Reasons for non-enrollment may include unplanned pregnancy, few social supports and structural barriers such as lack of transportation.2 For starters, we can “talk it up” during visits when a mother informs us she is expecting, we can collaborate with obstetrical colleagues to do the same, and any social determinants of health programs in our offices can routinely ask about enrollment; this may be an area for future research since the benefits to the soon-to-be-born child are so profoundly positive. Thanks to Alice Guan and colleagues for a thought-provoking and far-reaching study, pregnant with implications!
References
1. Driscoll AK, Osterman MJK. Maternal characteristics of prenatal WIC participation in the United States, 2016. NCHS Data Brief, no 298. Hyattsville, MD: National Center for Health Statistics. 2018.
2. Liu CH, Liu H. Concerns and Structural Barriers Associated with WIC Participation among WIC-Eligible Women. Public Health Nurs. 2016 Sep;33(5):395-402. doi: 10.1111/phn.12259. Epub 2016 Mar 9. PMID: 26956356; PMCID: PMC5527844.
3. Centers for Disease Control and Prevention (CDC). Eligibility and enrollment in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC)--27 states and New York City, 2007-2008. MMWR Morb Mortal Wkly Rep. 2013 Mar 15;62(10):189-93. PMID: 23486384; PMCID: PMC4604825.
