Impact of fruit and vegetable benefits on pregnancy outcomes among WIC participants: a natural experiment

Proper nutrition is critical for maternal and neonatal health. In January 2017, the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in San Francisco, California, began providing an additional $40 per month in fruit and vegetable (F&V) benefits to pregnant clients with the goal of improving food security and nutrition-related outcomes. We evaluated whether pregnant women on WIC who received this additional F&V benefit exhibited better perinatal and birth outcomes compared with those who received standard WIC benefits. We used 2010–2019 birth certificate data from the National Center for Health Statistics. The intervention group consisted of WIC participants living in San Francisco (SF) County (intervention county) and whose first trimester started after January 2017. We used a quasi-experimental synthetic control method to compare trends between the intervention and control groups (a weighted sample of other California counties that did not distribute additional F&V benefits). Outcomes included low birth weight, preterm birth, small-for-gestational-age, gestational diabetes, and gestational weight gain. No significant differences in maternal and neonatal outcomes among WIC recipients in SF and synthetic control group were observed after the F&V benefits were distributed. Prior studies have shown that additional F&V benefits have positive effects on maternal and infant outcomes, indicating that F&V vouchers are a promising strategy for supporting equitable health outcomes. Our null results suggest that more rigorous research is needed to determine their optimal dose and duration, especially in high-cost-of-living areas, and to examine more upstream and structural interventions.