Mothers enrolled in the Special Supplementary Feeding Program for Women, Infants, and Children (WIC) may experience improved birth outcomes and a lower risk of infant mortality, according to a systematic review.
S.Michelle Ogunwole, MD, of the Johns Hopkins University School of Medicine, and colleagues reported that women who participated in WIC had reduced risks of preterm labor (10% to 15%) and low birth weight (11% to 24%).
Women, Infants, and Children (WIC) participation was also associated with a 14% to 40% lower risk of infant mortality, researchers report in Annals of internal medicine.
While the strength of the evidence showing a reduced risk of infant mortality was rated moderate, indicating that the conclusions could be strengthened with more data, the findings “continue to underscore the importance of WIC as part of the country’s public health infrastructure,” the investigators wrote.
They also identified some studies that showed differences in associations between WIC participation and adverse birth outcomes as well as infant mortality by race and ethnicity, with a greater reduction in risk among black women.
“More evidence is needed to assess whether participation in the Women, Infants, and Children (WIC) program may provide differential benefits by race and ethnicity,” the researchers wrote. “This is important, because maternal mortality, morbidity, and neonatal and neonatal outcomes are pressing public health issues characterized by income and significant racial and ethnic disparities.”
WIC was created in 1974 to serve low-income women and their children under 5 years of age, provide nutrition and breastfeeding education, referral to medical and social service providers, and support high-risk pregnancies. In 2009, the WIC food package was changed to align with recommendations made by the National Academies of Sciences, Engineering, and Medicine to reduce diet-related chronic disease.
Ogunwole and co-authors conducted the systematic review as part of a larger evidence report commissioned by the USDA to examine the latest evidence for the association between WIC participation and maternal outcomes and health. The analysis included studies published between January 2009 and April 2022.
The researchers identified 20 observational studies, 19 of which reported direct evidence. There were seven cohort studies, 11 cross-sectional studies, one case-control study, and a study evaluating change of the 2009 food package that provided indirect evidence for delivery outcomes.
Ogunwole and colleagues found moderate strength of evidence that WIC involvement was associated with a lower risk of preterm birth and lower birth weight.
Three studies provided direct evidence for the association between WIC involvement and preterm birth. A large national cohort study of 11 million mothers between 2011 and 2017 showed that mothers enrolled in the Women, Infants and Children program had a 12% reduced risk of preterm birth (0.88, 95% CI 0.86-0.87).
In addition, the authors concluded that WIC participation was associated with lower odds of low birth weight based on evidence from three studies with consistent results. For example, a retrospective cohort study of more than 200,000 participants found that mothers enrolled in WIC had an approximately 20% lower risk of having a low birth weight child (hazard ratio 0.81, 95% CI 0.69-0.97).
Two studies provided direct evidence for infant mortality, which was defined as the death of an infant less than a year old. A large national cohort study reported a 16% lower odds of infant mortality among mothers enrolled in WIC (rate of change 0.84, 95% CI 0.83–0.86), and an older study of nearly 3,000 infants in Puerto Rico confirmed these findings.
Ogunwole and co-authors said their findings highlighted several knowledge gaps regarding the impact of WIC on health outcomes. For example, there was no direct evidence describing the relationship between WIC and maternal morbidity and mortality, and only low-quality evidence of gestational weight gain. There was also insufficient evidence for a relationship between WIC participation and childhood health outcomes, such as receiving vaccinations.
The team said that the study’s limitations included that the results were based on data from observational studies, and that there was a high potential for selection bias, whether or not the subjects in the study chose to participate in WIC. The researchers note that participation status was also self-reported in most of the studies reviewed.
“Overall, this review highlights the need for high-quality evidence about the association of maternal and child WIC participation with maternal, infant and child health outcomes,” Ogunwole and colleagues wrote. They called for further study of participant characteristics, as well as the timing and duration of WIC participation, “given the potential of WIC to reduce disparities in maternal, infant and child health.”
The study was funded by the Agency for Healthcare Research and Quality.
Ogunwole reported no conflict of interest; The co-authors reported financial relationships with the National Institute of Diabetes and Digestive and Kidney Diseases and the Maryland Department of Health.