TY - JOUR T1 - PRepregnancy obesity as a risk factor for structural birth defects AU - Waller D, Shaw GM, Rasmussen SA, et al Y1 - 2007/08/01 N1 - 10.1001/archpedi.161.8.745 JO - Archives of Pediatrics & Adolescent Medicine SP - 745 EP - 750 VL - 161 IS - 8 N2 - Objective  To describe the relation between maternal obesity, overweight and underweight status, and 16 categories of structural birth defects.Design  An ongoing multisite, case-control study. Clinical geneticists reviewed all of the cases, excluding those that had or were strongly suspected to have a single-gene disorder or chromosomal abnormality. Mothers with preexisting diabetes were also excluded. Body mass index was based on maternal report of height and weight prior to pregnancy.Setting  Eight participating states in the United States.Participants  Mothers enrolled in the National Birth Defects Prevention Study who had index pregnancies between October 1, 1997, and December 31, 2002.Main Exposure  Maternal obesity.Main Outcome Measures  Crude and adjusted odds ratios.Results  Mothers of offspring with spina bifida, heart defects, anorectal atresia, hypospadias, limb reduction defects, diaphragmatic hernia, and omphalocele were significantly more likely to be obese than mothers of controls, with odds ratios ranging between 1.33 and 2.10. Mothers of offspring with gastroschisis were significantly less likely to be obese than mothers of controls.Conclusions  To our knowledge, this is the first population-based study of its scale to examine prepregnancy obesity and a range of structural birth defects. These results suggest a weak to moderate positive association of maternal obesity with 7 of 16 categories of birth defects and a strong inverse association with gastroschisis. The mechanisms underlying these associations are not yet understood but may be related to undiagnosed diabetes. SN - 1072-4710 M3 - doi: 10.1001/archpedi.161.8.745 UR - http://dx.doi.org/10.1001/archpedi.161.8.745 ER -