Maternal and neonatal risks and benefits associated with bariatric surgery

Reference

Kwong W, Tomlinson G, Feig DS. Maternal and neonatal outcomes after bariatric surgery; a systematic review and meta-analysis: do the benefits outweigh the risks? Am J Obstet Gynecol 2018;218(6);573-580.

Synopsis

This well-designed meta-analysis assessed the risks and benefits associated with bariatric surgery for subsequent pregnancy outcomes. The authors included 20 cohort studies, with 2.8 million women, 8364 of whom had bariatric surgery and subsequent pregnancy. The authors required selected studies to have comparison groups, with the primary analysis restricted to those with control patients matched for body mass index prior to bariatric surgery. The search included studies published up to December 2016; the studies were generally of high quality. The authors would have included randomized controlled trials, but none were identified. They calculated pooled odds ratios (ORs) and numbers needed to treat (NNTs) or numbers needed to treat to harm (NNTHs) as reciprocals of absolute risk differences. They found reduced rates of (1) gestational diabetes (OR 0.20; 95% CI 0.11 - 0.37; NNT = 5), (2) large-for-gestational-age infants (OR 0.31; 0.17 - 0.59; NNT = 6), (3) hypertensive disorders (OR 0.38; 0.27-0.53; NNT = 8), (4) cesarean deliveries (OR 0.50; 0.38 - 0.67; NNT = 9). They also found increased rates of (1) small-for-gestational-age infants (OR 2.16; 1.34 - 3.48; NNTH = 21) and (2) preterm deliveries (less than 37 weeks' gestation) (OR 1.35; 1.02 - 1.79; NNTH = 35). There were no differences found for many other outcomes, including preeclampsia, neonatal intensive care admissions, stillbirths, malformations, or neonatal deaths. Malabsorptive surgeries, such as Roux-en-Y or biliopancreatic diversion, tended to produce more marked effects than restrictive surgeries (gastric banding or gastroplasty) on both large- and small-for-gestational-age outcomes.