While losing weight does not improve a woman’s fertility, her sexual function does, say Penn State College of Medicine researchers, who reported their findings in the Journal of Clinical Endocrinology and Metabolism.
Richard Legro, M.D. explained that obese women have problems ovulating, which affects fertility. “Obesity, especially centered in the abdomen, among infertile women seeking pregnancy is also associated with poor response to ovulation induction and with decreased pregnancy rates.”
Doctors usually tell obese women who want to get pregnant to lose weight. Dr. Legro and team set out to determine what impact gastric bypass surgery might have on women’s reproductive function.
As a large amount of weight is lost after bariatric surgery in a short period, the team thought this would be a good way to examine the effects of weight loss on reproductive function in women. Each patient can be observed while they are obese and after undergoing surgery to identify any changes.
The study involved 29 morbidly obese women. An obese person has a BMI (body mass index) of 30 or more, while a morbidly obese individual’s BMI is 40 or more. People who are morbidly obese have accumulated so much body fat that it may have an adverse effect on their health. All the women were of reproductive age. They were followed for two years after Roux en Y gastric bariatric bypass surgery.
The researchers collected daily urine samples over the course of a menstrual cycle to determine ovulation frequency and quality. They were surprised to find that ovulation rates stayed high – over 90% during all their checks before surgery, and then afterwards at 1, 3, 6, 12 and 24 months.
There was no change in the quality of ovulation. Losing weight did not have a significant effect on the ovarian cycle.
They did find a notable shortening of eight to nine days during the follicular phase. The follicular phase is the period from the end of the previous menstrual flow up to ovulation (when the egg is released). Within three months, after surgery, the follicular phase was found to be 6.5 days shorter, and then at 24 months 9 days shorter.
Obese women tend to have longer menstrual cycles because their follicular phase is longer. Nobody knows why this phase shortens when an obese woman loses weight.
The researchers used the Female Sexual Function Index, which consists of a series of questionnaires. They found that bariatric surgery significantly improved the women’s sexual function. They said that the improvement was independent of any changes in the women’s body composition or hormone levels.
The greatest improvements were in sexual desire and arousal. The study did not ask about sexual activity or desire to become pregnant. The authors suggest that if sexual desire increased, then logically the frequency of sexual activity would too.
“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.”
A team of doctors from the University of Iowa Hospitals and Clinics in Iowa City reported in the 28th Annual Meeting of the American Society for Metabolic & Bariatric Surgery, in June 2011, that bariatric surgery may help obese women’s fertility, especially those with PCOS (polycystic ovarian syndrome). PCOS is a hormonal imbalance that affects up to 10% of women of reproductive age. 33% to 50% of females with PCOS are overweight/obese.
Senior researcher, Mohammad Jamal, MD, FACS, said:
“Not many patients come to a bariatric surgeon to treat infertility problems. But this study suggests that women with morbid obesity, who are infertile secondary to PCOS, may have a new surgical option. Many other studies have shown bariatric surgery can improve or resolve a multitude of diseases and conditions. It appears that infertility now joins that list.”
The team followed up after surgery and found that fertility did improve among the women who wanted to get pregnant. However, the number of participants was small.
Written by Christian Nordqvist