Obstetrical and neonatal outcomes in women following gastric bypass: a Danish national cohort study.

OBJECTIVE To assess obstetrical and neonatal outcomes in women following gastric bypass, compared with adipose women without surgery and with a normal weight control population. DESIGN Historical controlled cohort study. SETTING Denmark. POPULATION All women undergoing gastric bypass during the period 1996-2011, and subsequently giving birth. METHODS AND MAIN OUTCOME MEASURES Obstetrical and neonatal outcomes in women without gastric bypass matched on age, parity, plurality, year, and body mass index, and normal weight women. RESULTS In 415 women giving birth after gastric bypass we found significantly more women with hypertension in pregnancy; relative risk (RR) 2.5 (95% confidence interval 1.3-5.0), gestational diabetes; RR = 6.9 (3.5-13.5), and acute abdominal pain during pregnancy; RR = 4.7 (2.9-7.8) compared with normal weight controls. Compared with women with similar body mass index, they had a lower incidence of preeclampsia and emergency cesarean sections, and their children a lower incidence of asphyxia; RR = 0.4 (0.2-0.8). Their children were on average 212 g smaller than newborn of normal weight mothers, and 319 g smaller than newborn of adipose controls, and had significantly more admissions to neonatal intensive care unit compared with newborn of normal weight mothers; RR = 1.5 (1.1-2.0). CONCLUSIONS Gastric bypass may reduce the risk of preeclampsia, emergency cesarean section, and perinatal asphyxia, compared with adipose women without surgery. Compared with normal weight controls women who had had a gastric bypass had a higher risk of hypertension, gestational diabetes, and acute abdominal pain during pregnancy and their children a lower birthweight and higher incidence of admittance to neonatal intensive care.