Will Losing Weight Improve Fertility?
A study published in Fertility and Sterility, May 2014, looked at a group of overweight infertile women who were counseled on weight reduction and assisted with medication, when needed, to help achieve their goal. Those included in the study, patients had to have a BMI (body mass index) of greater than or equal to 25-kg/sq. meter. Patients had all been attempting to conceive for at least one year. Each patient included in the study was referred to an endocrinologist for weight loss counseling and was seen at least once. All included patients were available for follow-up for at least 18 months following their initial consultation with the medical endocrinologist. The goal set for the patients was referred to as “meaningful weight loss”, and was defined as 10% of maximum body weight. Patients were encouraged to restrict calories and exercise for 30 minutes each day. They were called or emailed weekly by a member of the study team. Patients with elevated blood sugars were treated with metformin, and those who had difficulty meeting their weight loss goal of 10% of body weight were offered an appetite suppressant, phentermine, and were instructed not to attempt conceiving while on this medication. During the 18 months that followed the initial weight loss consultation, patients continued to attempt to conceive. Most patients continued with active fertility treatments during this time interval.
Fifty-two patients were included in the study. Of these 52 patients, 17 achieved their goal of meaningful weight loss (greater than 10% of body weight), and 35 did not. The conception and live birth rates for those who achieved their goal were 88% and 71% respectively. The conception and live birth rates for those patients who did not achieve meaningful weight loss were 54% and 37% respectively. For patients who conceived during the 18 months without treatment, the conception rates were 35% for those who achieved meaningful weight loss compared to 17% for those who did not.
Among patients with recurrent pregnancy loss, those who achieved 10% weight loss had live birth rates that were twice as high as the group that did not (67% vs. 33%).
The main criticisms of this study are that it is retrospective and that the number of patients included in the study is small (52). The authors also point out that because lifestyle interventions were involved, it is possible that part of the observed improvement in fertility could be the result of improvements in sperm counts of male partners. Since a patient’s weight is a modifiable contributor to infertility, it makes sense to encourage overweight infertile patients to lose weight. This study provides hard evidence that significant improvements in fertility accompany weight loss in overweight patients.