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Does Weight Loss Improve Ovulation?
November 1, 2012
Especially for the infertility patient with Polycystic Ovarian Syndrome (PCOS), weight gain and loss is a common concern. PCOS plagues 10% of women of reproductive age and somewhere between 33-50% of these women are overweight or obese. A study out of Penn State College of Medicine and published in the Journal of Clinical Endocrinology and Metabolism says weight loss might not improve fertility, but can improve attitudes toward sex and its frequency.
Belly weight, or weight centered in the abdomen rather than the hips or thighs, is detrimental to the infertility patient in that it is thought to be associated with a poor response to ovulation induction, the portion of a fertility treatment cycle that involves ovarian stimulation to produce follicles and later ovulation trigger. Many patients with this type of weight may recall a time when their doctor has advised them to lose weight.
Richard Legro, M.D., F.A.C.O.G., Primary Investigator and physician at Penn State Hershey Obstetrics and Gynecology, decided to put this theory to the test. If belly weight is a road block to ovulation, would gastric bypass surgery improve ovulatory function? Legro’s research team utilized gastric bypass surgery because a large amount of weight is typically lost after this procedure. This would measure two extreme conditions and pinpoint changes easily.
Twenty-nine morbidly obese women with a BMI of 40 or more were selected to participate in the study. All of these women were of reproductive age and were followed for 2 years after gastric bariatric bypass surgery. PCOS was not an inclusion criteria for this study. Daily urine samples were collected over the course of the women’s menstrual cycles. The team looked for ovulation frequency and quality, and discovered that ovulation rates held at 90% before surgery and across five subsequent follow-ups over the course of those 2 years.
Surprisingly, weight loss did not have an effect on ovulation. Instead, they noticed a shortened number of days between the end of menses and ovulation.
An unexpected result of the study was improved sexual function as recorded on the Female Sexual Function Index, a series of questionnaires examining desire and arousal. It is believed that an increase in sexual desire leads to greater sexual frequency.
"The effects of weight loss on reproductive function are more modest than we hypothesized. In terms of ovulation, there doesn't appear to be a window after surgery where fertility is improved. The door appears to be open at all times. Other factors may be involved with infertility in obese women, such as diminished sexual desire and thus less intercourse. This study, to our knowledge, is the largest, most comprehensive and longest study of female reproductive function before and after Roux en Y gastric bariatric surgery”, Legro said of the results.
So what about the effects of weight loss on ovulation in women with PCOS? Another study presented at the 2011 Annual Meetings of the American Society for Metabolic and Bariatric Surgery by the University of Iowa Hospitals and Clinics in Iowa City found that bariatric surgery did improve fertility in obese women, particularly those with PCOS. This data is limited as few women seek gastric bypass surgery to treat infertility. Further research is needed to form conclusions on the success of weight loss surgery for inducing ovulation.
To read the full article, click here.