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Perinatal Outcomes After Bariatric Surgery Compared With a Matched Control Group
Marie J Boller1, Fei Xu, Catherine Lee
1Department of Obstetrics and Gynecology and the Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, the Permanente Medical Group, and the Kaiser Permanente Northern California Division of Research, Oakland, and the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, California.
Insights
Pregnancy after bariatric surgery is linked to lower rates of preeclampsia, gestational diabetes, and large-for-gestational-age (LGA) neonates. However, it is associated with a higher risk of small-for-gestational-age (SGA) neonates.
Area of Science:
- Obstetrics and Gynecology
- Bariatric Surgery Outcomes
- Perinatal Health
Background:
- Bariatric surgery significantly impacts patient health, necessitating an understanding of pregnancy outcomes post-procedure.
- Evaluating perinatal risks and benefits is crucial for guiding patient care and counseling.
Purpose of the Study:
- To assess perinatal outcomes in pregnancies following bariatric surgery.
- To compare outcomes between patients with and without a history of bariatric surgery using propensity score matching.
Main Methods:
- Retrospective cohort study of 1,591 pregnancies post-bariatric surgery and 7,955 matched controls (2012-2018).
- Propensity score matching accounted for numerous demographic and clinical variables.
- Modified Poisson regression analyzed primary outcomes: preterm birth, gestational hypertension, preeclampsia, diabetes, LGA/SGA neonates, and cesarean delivery.
Main Results:
- Pregnancy after bariatric surgery showed reduced risks of preeclampsia (aRR 0.72), gestational diabetes (aRR 0.73), and LGA neonates (aRR 0.56).
- An increased risk of small-for-gestational-age (SGA) neonates was observed (aRR 1.51).
- No significant differences were found in preterm birth, gestational hypertension, or cesarean delivery rates.
Conclusions:
- Pregnancy following bariatric surgery is associated with a lower incidence of preeclampsia, gestational diabetes, and LGA neonates.
- There is an elevated risk of SGA neonates in pregnancies after bariatric surgery compared to controls.
- These findings are vital for managing pregnancies in women with a history of bariatric surgery.
Objective:
To evaluate perinatal outcomes associated with pregnancy after bariatric surgery within a large integrated health care system using propensity score matching.
Methods:
We conducted a retrospective cohort study that evaluated perinatal outcomes in pregnant patients after bariatric surgery from January 2012 through December 2018. History of bariatric surgery was identified by using International Classification of Diseases codes and a clinical database. Primary outcomes were preterm birth (PTB), gestational hypertension, preeclampsia, impaired glucose tolerance or gestational diabetes, a large-for-gestational-age (LGA) or small-for-gestational-age (SGA) neonates, and cesarean birth. Propensity scores were estimated by using logistic regression that accounted for age at delivery, prepregnancy body mass index, year of delivery, parity, neighborhood deprivation index, race and ethnicity, insurance status, initiation of prenatal visit in the first trimester, smoking during pregnancy, chronic hypertension, and preexisting diabetes. Five patients in the control group were matched to each patient in the case group on linear propensity score, and modified Poisson regression was used to adjust for covariates. Sensitivity analyses by timing and type of surgery were performed.
Results:
We identified a case cohort of 1,591 pregnancies in patients after bariatric surgery and a matched cohort of 7,955 pregnancies in patients who had not undergone bariatric surgery. Demographic characteristics were similar in both groups. In multivariate models, pregnancy after bariatric surgery was associated with a decreased risk of preeclampsia (7.5% vs 10.2%, adjusted relative risk [aRR] 0.72, 95% CI 0.60-0.86), gestational diabetes or impaired fasting glucose (23.5% vs 35.0%, aRR 0.73, 95% CI 0.66-0.80), and LGA (10.6% vs 19.9%, aRR 0.56, 95% CI 0.48-0.65) and an increased risk of SGA (10.9% vs 6.6%, aRR 1.51, 95% CI 1.28-1.78). No significant differences were observed in PTB, gestational hypertension and cesarean delivery.
Conclusion:
Pregnancy after bariatric surgery in a racially and ethnically diverse cohort of patients is associated with decreased risk of preeclampsia, gestational diabetes or impaired fasting glucose, and LGA neonates; it is also associated with an increased risk of SGA neonates compared with pregnant patients in a matched control group.
