Pregnancy after bariatric surgery--a review of benefits and risks

Background: When other weight loss attempts have failed, bariatric surgery offers a successful alternative for obesity. Since operations are performed during women's reproductive years, the number of pregnant women with prior bariatric surgery is increasing. Bariatric surgery results in restriction of food intake and/or malabsorption leading to weight loss, but may induce a risk for malnutrition and pregnancy complications.

Method: Systematically conducted review addressing pregnancy after bariatric surgery using the PubMed and Cochrane databases.

Main outcome measures: Birthweight, gestational age, birth defects, preeclampsia, gestational diabetes mellitus, and mode of delivery.

Results: We included 17 articles in English, comparing pregnancies in women with prior bariatric surgery to pregnancies in a control group without this. There was considerable heterogeneity in study design and six of the studies included <50 women with bariatric surgery. Eight studies described lower birthweight and lower risk of macrosomia after bariatric surgery, but in six there was no difference. Five studies indicated a higher risk of small-for-gestational age infants, but only compared with non-obese women or severely obese controls. There was no difference in gestational length. Only one study suggested a higher risk of birth defects after surgery. The maternal risk of preeclampsia and gestational diabetes mellitus was lower after bariatric surgery. Results regarding mode of delivery are conflicting.

Conclusion: Pregnancy after bariatric surgery seems safe but larger studies matching or adjusting for body mass index are needed to improve the surveillance of these pregnancies and to assist in preventing adverse outcomes.