Maternal and neonatal outcomes after bariatric surgery; a systematic review and meta-analysis: do the benefits outweigh the risks?

Obesity during pregnancy is associated with a number of adverse obstetric outcomes that include gestational diabetes mellitus, macrosomia, and preeclampsia. Increasing evidence shows that bariatric surgery may decrease the risk of these outcomes. Our aim was to evaluate the benefits and risks of bariatric surgery in obese women according to obstetric outcomes. We performed a systematic literature search using MEDLINE, Embase, Cochrane, Web of Science, and PubMed from inception up to December 12, 2016. Studies were included if they evaluated patients who underwent bariatric surgery, reported subsequent pregnancy outcomes, and compared these outcomes with a control group. Two reviewers extracted study outcomes independently, and risk of bias was assessed with the use of the Newcastle-Ottawa Quality Assessment Scale. Pooled odds ratios for each outcome were estimated with the Dersimonian and Laird random effects model. After a review of 2616 abstracts, 20 cohort studies and approximately 2.8 million subjects (8364 of whom had bariatric surgery) were included in the metaanalysis. In our primary analysis, patients who underwent bariatric surgery showed reduced rates of gestational diabetes mellitus (odds ratio, 0.20; 95% confidence interval, 0.11-0.37, number needed to benefit, 5), large-for-gestational-age infants (odds ratio, 0.31; 95% confidence interval, 0.17-0.59; number needed to benefit, 6), gestational hypertension (odds ratio, 0.38; 95% confidence interval, 0.19-0.76; number needed to benefit, 11), all hypertensive disorders (odds ratio, 0.38; 95% confidence interval, 0.27-0.53; number needed to benefit, 8), postpartum hemorrhage (odds ratio, 0.32; 95% confidence interval, 0.08-1.37; number needed to benefit, 21), and caesarean delivery rates (odds ratio, 0.50; 95% confidence interval, 0.38-0.67; number needed to benefit, 9); however, group of patients showed an increase in small-for-gestational-age infants (odds ratio, 2.16; 95% confidence interval, 1.34-3.48; number needed to harm, 21), intrauterine growth restriction (odds ratio, 2.16; 95% confidence interval, 1.34-3.48; number needed to harm, 66), and preterm deliveries (odds ratio, 1.35; 95% confidence interval, 1.02-1.79; number needed to harm, 35) when compared with control subjects who were matched for presurgery body mass index. There were no differences in rates of preeclampsia, neonatal intensive care unit admissions, stillbirths, malformations, and neonatal death. Malabsorptive surgeries resulted in a greater increase in small-for-gestational-age infants (P=.0466) and a greater decrease in large-for-gestational-age infants (P=<.0001) compared with restrictive surgeries. There were no differences in outcomes when we used administrative databases vs clinical charts. Although bariatric surgery is associated with a reduction in the risk of several adverse obstetric outcomes, there is a potential for an increased risk of other important outcomes that should be considered when bariatric surgery is discussed with reproductive-age women.

Kwong W ，Tomlinson G ，Feig DS 《-》

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

This study aimed to systematically investigate a wide range of obstetrical and neonatal 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. We searched PubMed, Scopus, and Embase systematically from inception up to April 30, 2021. 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. 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 outcomes 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. Heterogeneity 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 Recommendations, Assessment, Development, and Evaluations) tool within the summary of findings table. 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% confidence interval, 0.18-0.35; I2, 0%; P<.00001), decreased gestational hypertension/preeclampsia (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 gastric bypass (malabsorptive procedure) resulted in greater decrease of large for gestational age, gestational hypertension/preeclampsia, and gestational 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. 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 periconception biochemical profile, congenital malformations, and reproductive health outcomes for both interventions; thus, future well-designed prospective studies are needed to further characterize these outcomes.

Mustafa HJ ，Javinani A ，Seif K ，Aghajani F ，Makar EJ ，Selhorst S ，Crimmins S ... -  《-》

Gestational weight gain below instead of within the guidelines per class of maternal obesity: a systematic review and meta-analysis of obstetrical and neonatal outcomes.

This study aimed to systematically investigate a wide range of obstetrical and neonatal outcomes as they relate to gestational weight gain less than the current Institute of Medicine and the American College of Obstetricians and Gynecologists guidelines when compared with weight gain within the guideline range and to stratify outcomes by the class of obesity and by the type of study analysis. We systematically searched studies on PubMed, Scopus, Embase, and the Cochrane Library from 2009 to April 30, 2021. Studies reporting on obstetrical and neonatal outcomes of singleton pregnancies related to gestational weight gain less than the current Institute of Medicine and the American College of Obstetricians and Gynecologists guidelines in comparison with weight gain within the guidelines among women with obesity overall (body mass index >30 kg/m2) and/or a specific class of obesity (I: body mass index, 30-34.9 kg/m2; II: body mass index, 35-39.9 kg/m2; and III: body mass index >40 kg/m2). Among the studies that met the inclusion criteria, multiple obstetrical and neonatal outcomes were tabulated and compared between pregnancies with weight gain less than recommended in the guidelines and those with weight gain within the guidelines, further classified by the class of obesity if applicable. Primary outcomes included small for gestational age neonates, large for gestational age neonates, preeclampsia, and gestational diabetes mellitus. Secondary outcomes included cesarean delivery, preterm birth, postpartum weight retention, and composite neonatal morbidity. A meta-analysis of univariate and adjusted multivariate analysis studies was conducted. The random-effect model was used to pool the mean differences or odds ratios and the corresponding 95% confidence intervals. Heterogeneity was assessed using the I2 value. The Newcastle-Ottawa Scale was used to assess individual study quality. A total of 54 studies reporting on 30,245,946 pregnancies were included of which 11,515,411 pregnancies were in the univariate analysis and 18,730,535 pregnancies were in the adjusted multivariate analysis. In the meta-analysis of univariate studies, compared with women who gained weight as recommended in the guidelines, those who gained less than the weight recommended in the guidelines had higher odds of having a small for gestational age neonate among those with obesity class I and II (odds ratio, 1.30; 95% confidence interval, 1.17-1.45; I2=0%; P<.00001; and odds ratio, 1.56; 95% confidence interval, 1.31-1.85; I2=0%; P<.00001, respectively). However, the incidence of small for gestational age neonates was below the expected limits (<10%) and was not associated with increased neonatal morbidity. Furthermore, after adjusting for covariates, that difference was not statistically significant anymore. The difference was not statistically significant for class III obesity. Following adjusted multivariate analysis, no significant differences in small for gestational age rates were noted for any classes of obesity between groups. Significantly lower odds for large for gestational age neonates were seen in the group with gestational weight gain less than the recommended guidelines among those with obesity class I, II, and III (odds ratio, 0.69; 95% confidence interval, 0.64-0.73; I2=0%; P<.00001; odds ratio, 0.68; 95% confidence interval, 0.63-0.74; I2=0%; P<.00001; and odds ratio, 0.65; 95% confidence interval, 0.57-0.75; I2=34%; P<.00001, respectively), and similar findings were seen in the adjusted multivariate analysis. Women with weight gain less than the recommended guidelines had significantly lower odds for preeclampsia among those with obesity class I, II, and III (odds ratio, 0.71; 95% confidence interval, 0.63-0.79; I2=0%; P<.00001; odds ratio, 0.82; 95% confidence interval, 0.73-0.91; I2=0%; P<.00001; and odds ratio, 0.82; 95% confidence interval, 0.70-0.94; I2=0%; P=.006, respectively), and similar findings were seen in the adjusted multivariate analysis. No significant differences were seen in gestational diabetes mellitus between groups. Regarding preterm birth, available univariate analysis studies only reported on overall obesity and mixed iatrogenic and spontaneous preterm birth showing a significant increase in the odds of preterm birth (odds ratio, 1.42; 95% confidence interval, 1.40-1.43; I2=0%; P<.00001) among women with low weight gain, whereas the adjusted multivariate studies in overall obesity and in all 3 classes showed no significant differences in preterm birth between groups. Women with low weight gain had significantly lower odds for cesarean delivery in obesity class I, II, and III (odds ratio, 0.76; 95% confidence interval, 0.72-0.81; I2=0%; P<.00001; odds ratio, 0.82; 95% confidence interval, 0.77-0.87; I2=0%; P<.00001; and odds ratio, 0.87; 95% confidence interval, 0.82-0.91; I2=0%; P<.00001, respectively), and similar findings were seen in the adjusted multivariate analysis. There was significantly lower odds for postpartum weight retention (odds ratio, 0.20; 95% confidence interval, 0.05-0.82; I2=0%; P=.03) and lower odds for composite neonatal morbidity in the overall obesity group with low gestational weight gain (odds ratio, 0.93; 95% confidence interval, 0.87-0.99; I2=19.6%; P=.04). Contrary to previous reports, the current systematic review and meta-analysis showed no significant increase in small for gestational age rates in pregnancies with weight gain below the current guidelines for all classes of maternal obesity. Furthermore, gaining less weight than recommended in the guidelines was associated with lower large for gestational age, preeclampsia, and cesarean delivery rates. Our study provides the evidence that the current recommended gestational weight gain range is high for all classes of obesity. These results provide pertinent information supporting the notion to revisit the current gestational weight gain recommendations for women with obesity and furthermore to classify them by the class of obesity rather than by an overall obesity category as is done in the current recommendations.

Mustafa HJ ，Seif K ，Javinani A ，Aghajani F ，Orlinsky R ，Alvarez MV ，Ryan A ，Crimmins S ... -  《-》

Outcomes of pregnancy after bariatric surgery.

Johansson K ，Cnattingius S ，Näslund I ，Roos N ，Trolle Lagerros Y ，Granath F ，Stephansson O ，Neovius M ... -  《-》

Maternal and neonatal outcomes in women undergoing bariatric surgery: a systematic review and meta-analysis.

Obese women are at increased risk for many pregnancy complications, and bariatric surgery (BS) before pregnancy has shown to improve some of these. To review the current literature and quantitatively assess the obstetric and neonatal outcomes in pregnant women who have undergone BS. MEDLINE, EMBASE and Cochrane databases were searched using relevant keywords to identify studies that reported on pregnancy outcomes after BS. Pregnancy outcome in firstly, women after BS compared to obese or BMI-matched women with no BS and secondly, women after BS compared to the same or different women before BS. Only observational studies were included. Two investigators independently collected data on study characteristics and outcome measures of interest. These were analysed using the random effects model. Heterogeneity was assessed and sensitivity analysis was performed to account for publication bias. The entry criteria were fulfilled by 17 non-randomised cohort or case-control studies, including seven with high methodological quality scores. In the BS group, compared to controls, there was a lower incidence of preeclampsia (OR 0.45, 95% CI 0.25-0.80; P=0.007), GDM (OR 0.47, 95% CI 0.40-0.56; P<0.001) and large neonates (OR 0.46, 95% CI 0.34-0.62; P<0.001) and a higher incidence of small neonates (OR 1.93, 95% CI 1.52-2.44; P<0.001), preterm birth (OR 1.31, 95% CI 1.08-1.58; P=0.006), admission for neonatal intensive care (OR 1.33, 95% CI 1.02-1.72; P=0.03) and maternal anaemia (OR 3.41, 95% CI 1.56-7.44, P=0.002). BS as a whole improves some pregnancy outcomes. Laparoscopic adjustable gastric banding does not appear to increase the rate of small neonates that was seen with other BS procedures. Obese women of childbearing age undergoing BS need to be aware of these outcomes.

Galazis N ，Docheva N ，Simillis C ，Nicolaides KH ... -  《-》