Chapter 26: Bariatric Surgery and Pregnancy

INTRODUCTION

Obesity, defined as a body mass index (BMI) of 30 kg/m² or greater, is a growing epidemic. In the United States, 35% of adults and 17% of children are obese.¹ Obesity is associated with multiple medical morbidities, including type 2 diabetes mellitus, hypertension, heart disease, stroke, cancers, and obstructive sleep apnea. Obese women are at higher risk of adverse pregnancy outcomes when compared to women with a normal BMI.² Complications in pregnancy include gestational diabetes, gestational hypertension, preeclampsia, macrosomia, fetal anomalies, and need for cesarean section.

Weight loss can reduce the risks and complications of these medical conditions. Unfortunately, behavioral modifications and medical management prove to be unsuccessful in many individuals. Surgical therapy performed to manage obesity is the only effective and proven therapy for patients with severe obesity (BMI ≥ 35 kg/m²).³

Bariatric operations are some of the most commonly performed surgeries. In 2011, over 340,000 bariatric procedures were performed worldwide, with more than 120,000 procedures performed in North America.⁴ The majority of these surgeries are performed in reproductive-aged women.⁵ In addition, the use of bariatric surgery in the adolescent population is rising.⁶ This poses significant implications for women prior to and during pregnancy. Clinicians caring for reproductive-aged women need to be familiar with the various types of bariatric surgeries, the recommendations for management in pregnancy, and the associated complications and risks to both the patient and her fetus.

Current indications for bariatric surgery include a BMI of 40 kg/m² or greater or a BMI of 35 kg/m² or greater with comorbid medical conditions.⁷ Individuals meeting criteria should also have attempted and failed other weight loss treatments. In addition, patients are expected to be psychologically stable.

Weight loss from bariatric surgery occurs through two general mechanisms: restriction of intake or malabsorption of ingested food. Procedures may have a combination of both malabsorptive and restrictive components. The Roux-en-Y gastric bypass, which is a mixed malabsorptive-restrictive surgery, is the most commonly performed surgery for weight loss in the United States. It involves creation of a small gastric pouch that is directly connected to a portion of the jejunum known as the “Roux limb,” thereby bypassing the rest of the stomach and duodenum. The Roux limb is then linked to the remaining segment of intestine in a Y-shaped enteroenterostomy. The adjustable gastric band is another common procedure that is entirely restrictive in nature. It involves placement of a fluid-filled band around the fundus of the stomach, reducing its functional volume. Depending on the type of procedure performed, patients may be at risk for micronutrient deficiencies, decreased absorption of medications, dumping syndrome, and gastric ulcers. It is important for medical providers to consider these potential complications in pregnant women with a history of bariatric surgery.

Weight loss after bariatric surgery can restore the normal hormonal milieu, thereby ...