Maternal prepregnancy BMI and size at birth: race/ethnicity-stratified, within-family associations in over 500,000 siblings

To estimate racial/ethnic-stratified effects of maternal prepregnancy BMI on size for gestational age at birth, by comparing siblings within families. This study examined linked vital statistics and patient discharge data from 580,960 infants born to 278,770 women in the State of California (2007–2012). To control for family-level confounding, we used fixed effects multinomial regression, modeling size for gestational age (small [SGA],...