Contraception after bariatric surgery

5.1

Introduction

Bariatric surgery is the most effective treatment for morbid obesity. National Institute of Health has laid out criteria for a group of patients who should be considered suitable for bariatric surgery:

• 1.

  Body mass index (BMI)>40.

• 2.

  BMI of 30–40 plus one of the following obesity-related comorbidities: severe diabetes mellitus, Pickwickian syndrome, obesity-related cardiomyopathy, severe sleep apnoea, or osteoarthritis interfering with lifestyle.

Bariatric surgeries lead to weight loss and comorbidity improvement by the following mechanisms:

• 1.

  gastric restriction: reduction of amount of food that can be consumed;

• 2.

  malabsorption: impaired food-digestion by smaller stomach and nutrients absorption by shortened intestine; or

• 3.

  a combination of both.

These procedures result in changes in gut hormones that promote satiety and suppress hunger.

Most weight-loss surgeries today are performed using minimally invasive techniques (laparoscopic surgery).

The most common bariatric procedures are:

• 1.

  Adjustable gastric band: it is a commonly performed restrictive procedure, by placing an inflatable band around the upper portion of stomach, thus creating a small stomach pouch above the band.

  • a.

    Vertical band gastroplasty: sectioning off the cardia of the stomach by a longitudinal staple line and placing a band or mesh around the outlet.

  • b.

    Laparoscopic sleeve gastrectomy: removing approximately 80% of stomach.

  • c.

    Intragastric balloon.

  • d.

    Endoliminal gastroplasty.

• 2.

  Biliopancreatic diversion (BPD): this involves dividing the jejunum and connecting it near the ileocecal valve, thus bypassing a long segment of small bowel (this operation is no longer performed).

• 3.

  Roux-en-Y gastric bypass: this operation involves creating a small stomach pouch and then connecting to the small intestine further down.

• 4.

  BPD with duodenal switch: this procedure involves creating a smaller, tubular stomach pouch and connecting further down, bypassing a large portion of the small intestine.

5.2

Obesity and contraception issues

Historically, overweight and obese women have been excluded from trials in hormonal contraception. Therefore data regarding the safety and efficacy of contraceptive methods is lacking.

The effect of obesity on pharmacokinetics of steroidal contraceptives especially the risks of failure are poorly understood,

Obesity can have profound effects on absorption, enterohepatic metabolism, distribution, and excretion of hormones. Even our knowledge of pharmacokinetics of oral steroid contraceptives following bariatric surgery is poor.

Women need contraceptives with high efficacy in the context of physiological alterations within GI system, new pharmacokinetic adjustment, and weight stabilisation following bariatric surgery.

Research evidence:

There have been few studies to date that have investigated the pharmacokinetics of contraceptive steroids in obese women with or without bariatric surgery.

A Cochrane review of 17 studies involving different methods of contraception did not generally find any robust evidence for decreased efficacy of different contraceptive methods in overweight or obese women. However, it is recognised that combined hormonal contraceptives are associated with significantly increased risks such as venous thromboembolism (VTE).