Comparing Usual Dietary Intakes Among Subgroups of Mothers in the Year Before Pregnancy

The quantity and quality of dietary intake among women of reproductive age has important public health implications for nutritional status during pregnancy. We described dietary intake during the year before pregnancy among a large, diverse group of US mothers. We examined data from 11？109 mothers who gave birth from 1997 through 2011 and participated in a population-based case-control study, the National Birth Defects Prevention Study, as controls (mothers who had babies without major birth defects). We examined whether subgroups of mothers at elevated risk of adverse pregnancy outcomes were more likely than their reference groups to have high dietary intake (>90th percentile of intake) or low dietary intake (<10th percentile of intake). We examined dietary intake of 22 nutritional factors, which were estimated from responses to a food frequency questionnaire. Participants who were aged <20, were nulliparous, had