Prepregnancy Roux-en-Y gastric bypass vs sleeve gastrectomy: a systematic review, pairwise, and network meta-analysis of obstetrical and neonatal outcomes

OBJECTIVE: This study aimed to systematically investigate a wide range of obstetrical and neona-tal outcomes with respect to 2 types of prepregnancy bariatric surgery, Roux-en-Y gastric bypass and sleeve gastrectomy, through: (1) providing a meta-analysis of the effect of bariatric surgery (Roux-en-Y gastric bypass vs no surgery and, separately, sleeve gastrectomy vs no surgery) on adverse obstetrical and neonatal outcomes, and (2) comparing the relative benefit of Roux-en-Y gastric bypass vs sleeve gastrectomy using both conventional and network meta-analysis.DATA SOURCES: We searched PubMed, Scopus, and Embase systematically from inception up to April 30, 2021.ELIGIBILITY CRITERIA: Studies reporting on pregnancies' obstetrical and neonatal outcomes with respect to 2 types of prepregnancy bariatric surgery-Roux-en-Y gastric bypass and sleeve gastrectomy-were included. The included studies either indirectly compared between the procedure and controls or directly compared between the 2 procedures.METHODS: We performed a systematic review followed by pairwise and network meta-analysis in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta -Analyses) guidelines. In the pairwise analysis, multiple obstetrical and neonatal outcomes were tabulated and compared between 3 groups: (1) Roux-en-Y gastric bypass vs controls, (2) sleeve gastrectomy vs controls, and (3) Roux-en-Y gastric bypass vs sleeve gastrectomy. Primary out-comes included small for gestational age, large for gestational age, gestational hypertension/ preeclampsia, and gestational diabetes mellitus. Secondary outcomes included preterm birth, anemia, cesarean delivery, and biochemical profile. The random-effects model was used to pool the mean differences or odds ratios and the corresponding 95% confidence intervals. Het-erogeneity was assessed using the I2 value. The Newcastle-Ottawa scale was used to assess individual study quality. To resolve inconclusive findings and to rank current treatments, network meta-analysis was conducted for the primary outcomes. Quality of evidence was assessed with the Confidence in Network Meta-Analysis approach and the GRADE (Grading of Recommenda-tions, Assessment, Development, and Evaluations) tool within the summary of findings table.RESULTS: A total of 20 studies were included, reporting on 40,108 pregnancies, of which 5194 underwent Roux-en-Y gastric bypass, 405 underwent sleeve gastrectomy, and 34,509 were controls. Compared with controls, Roux-en-Y gastric bypass increased the risk of small for gestational age infants (odds ratio, 2.56; 95% confidence interval, 1.77-3.70; I2, 29.1%; P<.00001), decreased the risk of large for gestational age infants (odds ratio, 0.25; 95% con-fidence interval, 0.18-0.35; I2, 0%; P<.00001), decreased gestational hypertension/pre-eclampsia (odds ratio, 0.54; 95% confidence interval, 0.30-0.97; I2, 26.8%; P=.04), decreased gestational diabetes mellitus (odds ratio, 0.43; 95% confidence interval, 0.23 - 0.81; I2, 32%; P=.008), increased maternal anemia (odds ratio, 2.70; 95% confidence interval, 1.53-4.79; I2, 40.5%; P<.001), increased neonatal intensive care unit admission (odds ratio, 1.36; 95% confidence interval, 1.04-1.77; I2, 0%; P=.02), and decreased mean gestational weight gain (mean difference,-3.37 kg; 95% confidence interval,-5.62 to -1.11; I2, 65.3%; P=.003). Only 3 studies compared sleeve gastrectomy with controls, and found no significant differences in primary outcomes or in mean gestational weight gain. The network meta-analysis showed that Roux-en-Y gas-tric bypass (malabsorptive procedure) resulted in greater decrease of large for gestational age, gestational hypertension/preeclampsia, and gesta-tional diabetes mellitus, and a greater increase in small for gestational age infants when compared with sleeve gastrectomy (restrictive procedure). However, the small number of studies, small number of sleeve gastrectomy patients, limited outcomes, and data heterogeneity resulted in low-to -moderate network GRADE of evidence.CONCLUSION: This network meta-analysis showed that Roux-en-Y gastric bypass, compared with sleeve gastrectomy, resulted in greater decrease in large for gestational age, gestational hypertension/preeclampsia, and gestational diabetes mellitus, but in greater increase in small for gestational age infants. Certainty of evidence in the network meta-analysis was of a low-to-moderate GRADE. Evidence is still lacking for pericon-ception biochemical profile, congenital malformations, and reproductive health outcomes for both interventions; thus, future well-designed pro-spective studies are needed to further characterize these outcomes.