The impact of bariatric surgery on menstrual patterns

Obesity and anovulation are common medical problems in the United States. Anovulation in obese patients primarily manifests with irregular, sporadic or absent menstrual bleeding. Weight loss of at least 5% has been shown to reverse obesity-related anovulation. The aim of this study was to assess the impact of bariatric surgery on infertility in morbidly obese women and to identify factors associated with return of normal menses following bariatric surgery.

A survey of patients was collected from the bariatric surgery data-base at the Hospital of the University of Pennsylvania. 410 women under the age of 40 were sent questionnaires. 195 patients completed the questionnaire, and 29 patients had incorrect addresses without a forwarding address, resulting in a 51.2% response rate. Patients who reported menstrual cycle lengths >35 days were considered abnormal. 92 of the 195 responders were considered anovulatory preoperatively, based on menstrual history.

There was no significant difference in postoperative BMI, BMI decrease or age at surgery between the survey responders and non-responders. There was a significant difference between these 2 groups in time since surgery (P=.01). Both groups had a decrease in BMI of >18 kg/m(2). The mean menstrual cycle length preoperatively among those categorized as ovulatory and anovulatory was 27.3 and 127.5 days, respectively. Of the 98 patients who were anovulatory preoperatively, 70 patients (71.4%) regained normal menstrual cycles after surgery. Those patients who regained ovulation had greater weight loss than those who remained anovulatory (61.4 kg vs 49.9 kg, P=0.02).

Anovulation resulting in abnormal menses is a common problem in morbidly obese premenopausal women. The menstrual cycle disorders may completely resolve after bariatric surgery. Thus, infertility due to anovulation among morbidly obese women could potentially be viewed as an additional indication for bariatric surgery.