Bariatric Surgery Lowers Obesity Risks in Pregnancy

Obese women who undergo bariatric surgery have substantially lower rates of hypertensive complications during pregnancy, a large retrospective study found.

Compared with women who had bariatric surgery at a later time, those who had the surgery before delivery were 75% less likely to have any hypertensive disorder during pregnancy (OR 0.25, 95% CI 0.15 to 0.40), Wendy L. Bennett, MD, and colleagues from Johns Hopkins reported online in BMJ.

They also were less likely to have these specific hypertensive complications:

* Pre-eclampsia and eclampsia (OR 0.20, 95% CI 0.09 to 0.44)
* Chronic hypertension complicating pregnancy (OR 0.39, 95% CI 0.20 to 0.74)
* Gestational hypertension (OR 0.16, 95% CI 0.07 to 0.37)

Maternal obesity is a recognized risk factor for adverse perinatal outcomes, including gestational diabetes, hypertension, and congenital anomalies.

Maternal hypertension itself is associated with adverse outcomes such as preterm birth and intrauterine growth restriction.

In addition, the risk of cesarean delivery is almost three times greater for women with class II obesity (body mass index 35 or higher).

"Although the pathophysiology of these disorders is complex and not yet completely understood, interventions that reduce obesity have the potential to decrease their incidence and associated complications," the investigators wrote.

While some evidence existed suggesting that bariatric surgery can help reduce these risks, large studies had not examined the impact of the surgery and the severity of hypertensive disorders in pregnancy.

To assess this, Bennett and colleagues undertook a retrospective analysis of claims data from seven insurance plans in various parts of the country.

Among a sample of 585 obese women who had insurance claims for both delivery and bariatric surgery, the birth occurred before the mother had surgery in 269, and the delivery took place after the surgery in 316. In more than 80% of cases, the procedure used was gastric bypass.

Women whose deliveries took place before surgery were younger (31.3 versus 32.5 years, P<0.002) but had higher rates of pre-existing diabetes (23.4% versus 12.3%, P<0.001) and gestational diabetes (25.7% versus 13%, P<0.001).

Women who delivered before having surgery had higher rates of pre-eclampsia or eclampsia (15% versus 3%, P<0.001).

Those who gave birth before having the surgery also had higher rates of other hypertensive disorders:

* Gestational hypertension, 13% versus 2.5%, P<0.001
* Chronic hypertension complicating pregnancy, 13.8% versus 5.4%, P<0.001
* Pre-eclampsia or eclampsia with pre-existing hypertension, 12% versus 1%, P<0.001