Bariatric Surgery Prior to Pregnancy

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Obesity during pregnancy has been correlated with worse short-term and long-term outcomes for both mother and child. New research suggests that weight-loss surgery prior to pregnancy for the appropriate candidates may improve some, but not all, of these outcomes.

Risks of Obesity During Pregnancy

A woman who is pregnant and also obese can face several health challenges, including a higher likelihood of developing gestational diabetes, suffering a miscarriage, and requiring a C-section.

Additionally, pregnant women who are also obese have an increased risk of hypertension (high blood pressure) and complications from hypertension, known as preeclampsia and eclampsia, which may necessitate preterm delivery.

Risks to the Fetus

All of the potential complications of pregnancy listed above carry with them risks to the fetus as well. For instance, if a pregnant mother develops gestational diabetes, her fetus is more likely to weigh more than is normal for each stage of pregnancy (also known as gestational age), resulting in a heavier-than-average final birth weight.

Bariatric Surgery Prior to Getting Pregnant?

The term “bariatric surgery” applies to a number of surgical procedures that have been developed to treat obesity and surgically induce weight loss. These include gastric bypass operations as well as other procedures, such as gastric banding (lap band) and sleeve gastrectomy (gastric sleeve procedure), that have been developed for the surgical treatment of obesity.

According to the latest obesity guidelines released by the American Heart Association (AHA), the American College of Cardiology (ACC), and The Obesity Society (TOS), bariatric surgery may be an option for adult patients who meet certain criteria. These criteria include a body mass index (BMI) of 40 or greater, or a BMI of 35 or greater in a patient who has other medical conditions (known as “comorbid conditions”) caused by obesity.

The obesity guideline writing committee did not find sufficient evidence to recommend bariatric surgery for patients who have BMIs that fall below these cutpoints.

A recent study looked at over 600,000 pregnancies in the Swedish Medical Birth Register from 2006 through 2011, and found that 670 pregnancies had occurred in women who had previously undergone weight-loss surgery (bariatric surgery). The researchers found that these women were less likely to have gestational diabetes, and they were less likely to deliver babies who were large-for-gestational-age (i.e., heavier than average at birth).

However, these researchers also uncovered the possibility that women who had had bariatric surgery prior to pregnancy were twice as likely to have stillbirth or babies who died in the neonatal period (neonatal death), although these occurrences were rare (1.7%). The researchers found no significant increase or decrease in the frequency of congenital birth defects.

Experts in the field have pointed out that this finding of higher infant mortality may be a fluke, as prior medical literature has not suggested any association between bariatric surgery and infant mortality, and the statistics for this new study indicate that this finding is of only borderline statistical significance.

In addition, the kind of bariatric surgery procedure that was performed may make a difference. More studies and analyses in this area are eagerly awaited.


2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society [published online November 27, 2013]. Circulation.

Johansson K, Cnattingius S, Naslund I, et al. Outcomes of pregnancy after bariatric surgery. N Engl J Med 2015;372:814-824.

Caughey A. Bariatric surgery before pregnancy—is this a solution to a big problem? N Engl J Med 2015;372:877-878.

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