Impact of Bariatric Surgery on Hypertensive Disorders in Pregnancy: Retrospective Analysis of Insurance Claims Data

Abstract

Obese pregnant women are at high risk of adverse perinatal outcomes including hypertensive disorders of pregnancy. The most effective weight loss intervention for morbid obesity is bariatric surgery, which is associated with considerable improvement in several comorbidities. Previous studies have suggested that bariatric surgery reduces the risk of perinatal complications, but few studies have investigated the effect of this intervention using large national data sources, or examined its effect on hypertensive disorders of all severity during pregnancy. The aim of this retrospective cohort study was to determine whether women who delivered after bariatric surgery had lower rates of hypertensive disorders in pregnancy in comparison with obese women who delivered before bariatric surgery. Between 2002 and 2006, data from 7 insurance plans in the United States were analyzed to identify claims for pre-eclampsia and eclampsia, pre-eclampsia superimposed on hypertension, and gestational hypertension diagnoses among women with a history of at least 1 delivery. A total of 585 women aged 16 to 45 years who had undergone bariatric surgery and met eligibility criteria were identified. All participants had continuous insurance coverage during pregnancy and for 2 weeks after delivery. The primary study outcome measure was hypertensive disorders in pregnancy. Multiple logistic regression analysis was used to adjust for maternal age at delivery, multiple pregnancies, type of bariatric surgery, pre-existing diabetes complicating pregnancy, and insurance plan. Timing of delivery in relation to bariatric surgery (before and after surgery) was the independent variable. Of the 585 women, 269 delivered before bariatric surgery and 316 delivered after surgery. Most women underwent gastric bypass surgery (82%, 477/585). Women who delivered before bariatric surgery were slightly younger than those who delivered after surgery (mean age, 31.3 vs. 32.5 years, respectively; P < 0.002), but the other baseline characteristics of these two groups were similar. Compared with women who delivered before surgery, women who delivered after surgery had significantly lower rates of pre-existing diabetes (23.4% vs. 12.3%, P < 0.001) and gestational diabetes (25.7% vs. 13.0%, P < 0.001). Women who delivered after surgery also had substantially lower rates of chronic hypertension (adjusted odds ratio [aOR], 0.39; 95% confidence interval [CI], 0.20-0.74), gestational hypertension (aOR, 0.16; 95% CI, 0.07-0.37), and pre-eclampsia and eclampsia (aOR, 0.20; 95% CI, 0.09-0.44). These findings indicate that women who deliver after bariatric surgery have substantially lower rates of hypertensive disorders in subsequent pregnancies.