Obesity and Contraception: Emerging Issues

Amitasrigowri S. Murthy, M.D., M.P.H., F.A.W.G.


Semin Reprod Med. 2010;28(2):156-163. 

In This Article

Abstract and Introduction


Obesity is increasing in prevalence worldwide. Obese women are at similar risk of unintended pregnancy as normal weight women, although limited data are available on the effects of obesity on the efficacy of contraception. Conflicting data exist regarding efficacy of oral contraceptives in obese women, although trends of oral contraceptive failure are no higher than compared with those of normal weight women. The risk of venous thromboembolism is increased with obesity, and this risk may be additive when using a combined hormonal method. Bariatric surgery can lead to increased fertility; postoperative recommendations include avoiding pregnancy in the first year. Contraceptive use patterns in these women are largely unknown. Surgeons need greater awareness of the need for use of effective long-acting methods, and consensus guidelines need to be established.


Approximately half of all pregnancies in the United States are unintended, and about half of these are conceived while using some form of contraception.[1] Contraceptive counseling is made even more challenging by coexisting medical conditions including obesity. The World Health Organization (WHO) estimates that ~56.7% of reproductive-age women in the United States are overweight (body mass index [BMI] between 25 and 29.9 kg/m2) and >30% are obese (BMI >30 kg/m2).[2] There are increasing proportions of overweight and obese females in other developed nations as well. In the United Kingdom, >24% of reproductive age women are considered obese; in Australia 20% of women are considered obese.[3]

There are little data establishing a link between contraceptive use, its attendant risks of complications and failure, and obesity because most studies of new contraceptive methods exclude overweight women. Data that are available are both conflicting and limited by retrospective collection, underpowered studies, self-report of weight and contraceptive use, and the underreporting of unintended pregnancies that end in abortion. Moreover, a large number of these retrospective studies were conducted at a time when obesity was much less common.[4] There are also limited data on contraceptive options and their efficacy after bariatric surgery, an increasingly common treatment for the morbidly obese. This article reviews contraceptive efficacy and risks in obese women. It also examines available data on the impact of bariatric surgery.


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