Maternal, Fetal, and Infant Outcomes Associated With Bariatric Surgery: A Matched Cohort Study

The purpose of this study was to determine the association between bariatric surgery and maternal, fetal, and infant outcomes.

Obesity during pregnancy is a risk factor for adverse pregnancy outcomes. Bariatric surgery is the most effective weight loss treatment but the impact of bariatric surgery on pregnancy outcomes remains poorly characterized.

This was a population-based, matched cohort study of prospective databases in Ontario, Canada. Patients with obesity who received bariatric surgery from 2010 to 2016 and subsequently became pregnant matched on multiple factors to nonsurgical pregnant patients with obesity. The primary outcomes of interest were the incidence included of gestational diabetes, preeclampsia/hemolysis, elevated liver enzymes, and low platelets syndrome, small for gestational age, large for gestational age, and a composite of severe fetal/infant morbidity/mortality. Multivariable regression evaluated outcomes.

Six hundred eighty patients who underwent bariatric surgery and later became pregnant were matched to 2002 pregnant patients with obesity. Gestational diabetes occurred in 8.7% of the surgery group and 18.8% of the nonsurgical group [adjusted OR (aOR) 0.29, 95% CI: 0.21-0.40, P<0.001]. A lower incidence of preeclampsia/hemolysis, elevated liver enzymes and low platelets was observed postsurgery (aOR 0.20, 95% CI: 0.13-0.31, P<0.001). Bariatric surgery impacted small for gestational age (aOR 2.74, 95% CI: 2.04-3.70, P<0.001) and large for gestational age (aOR 0.25, 95% CI: 0.18-0.36, P<0.001). There were no observed associations between bariatric surgery and any adverse fetal or infant outcomes. A lower composite severe fetal/infant morbidity/mortality was observed postsurgery (aOR 0.73, 95% CI: 0.54-0.97, P<0.05).

Pregnancy after bariatric surgery appears safe and was associated with a reduced risk of several obesity related adverse pregnancy outcomes.