Impact of Pre-Pregnancy Weight and Gestational Weight Gain on Birth Outcomes by Nativity in the United States: A Systematic Review.

Background: Disparities in birth outcomes remain a problem in the United States. This study examined whether pre-pregnancy weight and gestational weight gain moderate the association between nativity and birth outcomes in the United States. Methods: We conducted a systematic review using Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. We searched PubMED, CINAHL, PsychInfo, and Cochrane Database of Systematic Reviews for relevant articles published before May 27, 2016. Results: Four articles met the eligibility criteria by adjusting for pre-pregnancy or gestational weight gain when examining birth outcomes by nativity. Results: Results from these studies show statistically significant differences in the risk of delivering low birth weight babies between foreign-born and U.S.-born women. These differences remained after adjusting for pre-pregnancy weight or gestational weight gain. However, results stratified by nativity still vary significantly by race/ethnicity. Conclusion: Few investigations include pre-pregnancy weight and gestational weight gain when examining differences in birth outcomes by nativity. Additional studies are needed to examine possible effect modification of these weight variables on the association between nativity and birth outcomes.