Impact of bariatric surgery on hypertensive disorders in pregnancy: retrospective analysis of insurance claims data

OBJECTIVE To determine whether women who had a delivery after bariatric surgery have lower rates of hypertensive disorders in pregnancy compared with women who had a delivery before bariatric surgery. DESIGN Retrospective cohort study. SETTING Claims data for 2002-6 from seven insurance plans in the United States. PARTICIPANTS 585 women aged 16-45 who had undergone bariatric surgery, had at least one pregnancy and delivery, and had continuous insurance coverage during pregnancy plus two weeks after delivery. MAIN OUTCOME MEASURE Hypertensive disorders in pregnancy defined with ICD-9 codes. The independent variable was the timing of delivery in relation to bariatric surgery, classified as deliveries before and after surgery. We used logistic regression to calculate odds ratios and confidence intervals for each type of hypertensive disorder in pregnancy. RESULTS Among the 585 women who had undergone bariatric surgery and had a delivery, 269 delivered before surgery and 316 delivered after surgery. Gastric bypass was the surgery in 82% (477) of all women. Women who delivered before surgery were younger at the time of delivery (mean age 31.3 v 32.5) but had higher rates of pre-existing diabetes and gestational diabetes mellitus. Compared with women who delivered before surgery, women who delivered after surgery had substantially lower rates of pre-eclampsia and eclampsia (odds ratio 0.20, 95% confidence interval 0.09 to 0.44), chronic hypertension complicating pregnancy (0.39, 0.20 to 0.74), and gestational hypertension (0.16, 0.07 to 0.37), even after adjustment for age at delivery, multiple pregnancy (that is, twins or more), surgical procedure, pre-existing diabetes, and insurance plan. CONCLUSION In this retrospective analysis of US women, bariatric surgery was associated with lower rates of hypertensive disorders in subsequent pregnancy.