Pre-pregnancy bariatric surgery associated with more neonatal morbidity and mortality

Reference

Akhter Z, Rankin J, Ceulemans D, et al. Pregnancy after bariatric surgery and adverse perinatal outcomes: A systematic review and meta-analysis. PLoS Med. 2019;16(8):e1002866.

Synopsis

We previously reported (https://www.essentialevidenceplus.com/content/poem/200731) a meta-analysis of 20 studies that demonstrated women who underwent bariatric surgery and subsequently became pregnant were less likely to develop gestational diabetes, hypertensive disorders, have large for gestational age infants and had fewer cesarean sections at the risk of higher rates of small for gestational age infants and preterm deliveries. To evaluate other perinatal outcomes, these authors searched multiple databases and Google Scholar to identify observational studies published in English that included women who had pre-pregnancy bariatric surgery. They also hand searched the reference lists of included studies. The authors don't describe if study inclusion or quality assessments were conducted independently by more than one author and just reported high interrater reliability for study inclusion and generally low risk of bias of the included studies. Ultimately, they included 33 studies comparing 14,880 women who became pregnant after bariatric surgery and 4 million pregnant women without bariatric surgery (not all of whom were obese). Sixteen studies combined women with all types of bariatric surgery, 14 restricted the analysis to those who underwent Roux-en-Y gastric bypass, six studies included only women with laparoscopic adjustable gastric banding, one included only sleeve gastrectomy, and one included biliopancreatic diversion. The authors identified marked variation among the control patients. Ten studies found higher mortality associated with prior bariatric surgery (OR 1.38, 95% CI 1.03-1.85). Additionally, ten studies found a higher rate of congenital anomalies following bariatric surgery (OR 1.29, 95% CI 1.04-1.59). The authors found no significant heterogeneity among these outcomes. Nineteen studies of pre-term birth provided data adequate for meta-analysis and showed preterm birth was significantly higher after surgery (OR 1.35, 95% CI 1.14-1.60), but with significant heterogeneity that partially resolved when considering the type of surgery: all types of surgery lumped together (OR 1.57, 95% CI 1.38-1.79), no difference for Roux-en-Y, laparoscopic adjustable gastric banding, or sleeve gastrectomy. Five studies of post-term births found a marked decrease in women who had prior surgery (OR 0.46, 95% CI 0.35-0.60 with no significant heterogeneity). Similar to the previously reported meta-analysis, this study also found a greater association between surgery and small for gestational age infants (OR 2.72, 95% CI 2.32-3.20) and a lower association for large for gestational age infants (OR 0.24, 95% CI 0.14-0.41). These observations were primarily with Roux-en-Y or biliopancreatic diversion and not so much for banding or sleeve procedures. Finally, infants born to women who had prior surgery were more likely to be admitted to the neonatal intensive care unit (OR 1.41, 95% CI 1.25-1.59 with no significant heterogeneity).The authors found no statistical evidence for publication bias for any of the outcomes except large for gestational age.