ATLANTIC-DIP: raised maternal body mass index (BMI) adversely affects maternal and fetal outcomes in glucose-tolerant women according to International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria

CONTEXT: Raised maternal body mass index (BMI) in association with hyperglycemia is associated with adverse pregnancy outcome. The contribution of raised BMI as an independent risk factor for adverse pregnancy outcome is of growing concern and increasing prevalence. OBJECTIVE: The aim of this study was to investigate the effects of raised maternal BMI on pregnancy outcome in glucose-tolerant women using the International Association of Diabetes and Pregnancy Study Groups criteria. PARTICIPANTS AND SETTING: We studied a cohort of glucose-tolerant, pregnant women (n = 3656) who were attending antenatal obstetric clinics and were recruited to a universal screening program for gestational diabetes under the ATLANTIC-DIP partnership. DESIGN: We conducted a prospective observational study of pregnancy outcome. Maternal outcomes include glucose, delivery mode, pregnancy-induced hypertension, preeclampsia, antepartum hemorrhage, and postpartum hemorrhage. Fetal outcomes included birthweight, congenital malformation, fetal death, neonatal jaundice, hypoglycemia, and respiratory distress. RESULTS: Increasing maternal BMI was associated with adverse pregnancy outcomes: higher cesarean section rates, preeclampsia, pregnancy-induced hypertension, increased birth weight, and congenital malformation. The association of glucose with adverse pregnancy outcome was weak and did not interact with raised BMI. A BMI threshold of 28 kg/m(2) was associated with a significant rise in adverse pregnancy outcome. CONCLUSIONS: Raised maternal BMI, within the overweight range, is associated with adverse pregnancy outcomes. These adverse effects of BMI occur independently of maternal glucose. It is apparent that pregnancy unmasks an underlying unhealthy metabolic milieu in obese and overweight women.