Impact of bariatric surgery on fetal growth restriction: experience of a perinatal and bariatric surgery center.

BACKGROUND: Bariatric surgery is known to improve some pregnancy outcomes, but there is concern that it may increase the risk of small for gestational age. OBJECTIVE: To assess the impact of bariatric surgery on pregnancy outcomes and specifically of the type of bariatric surgery on the risk of fetal growth restriction. STUDY DESIGN: A single-center retrospective case-control study. The study group comprised all deliveries in women who had undergone bariatric surgery. To investigate the effects of weight loss on pregnancy outcomes, we compared the study group with a control group matched for presurgery body mass index. Secondly, to assess the specific impact of the type of surgery on the incidence of fetal growth restriction in utero, we distinguished subgroups with restrictive and malabsorptive bariatric surgery, and compared outcomes for each of these subgroups with a second control group, matched for prepregnancy body mass index. RESULTS: Among 139 patients operated, 58 had a malabsorptive procedure (gastric bypass) and 81 a purely restrictive procedure (72 a gastric banding and 9 a sleeve gastrectomy). Compared with controls matched for presurgery body mass index, the study group had a decreased rate of gestational diabetes (12% vs 23%, P = .02) and large for gestational age >90th percentile (11% vs 22%, P = .01) but an increased rate of small for gestational age <10th percentile. The incidence of small for gestational age was higher after gastric bypass (29%) than it was after restrictive surgery (9%) or in controls matched for prepregnancy body mass index (6%) (P < .01 between bypass and controls). In multivariable analysis, after adjustment for other risk factors, gastric bypass remained strongly associated with small for gestational age (adjusted odds ratio, 7.16; 95% confidence interval, 2.74-18.72). CONCLUSION: Malabsorptive bariatric surgery was associated with an increased risk of fetal growth restriction.