Weight loss does not improve fertility

October 17, 2012

(Medical Xpress)—Losing weight does not lead to improved fertility in women, but does improve sexual function, according to Penn State College of Medicine researchers.

"Obesity in women has been linked to lack of ovulation and thus infertility," said Richard Legro, M.D., professor of obstetrics and gynecology. "Obesity, especially centered in the abdomen, among seeking pregnancy is also associated with poor response to ovulation induction and with decreased ."

are often told to lose weight prior to conception, so researchers looked at changes in reproductive function after gastric bypass surgery. One way to learn more about the effects of obesity on reproduction is to study women after bariatric surgery, since a large amount of weight is lost in a relatively short period of time. Each person can be studied while obese and after surgery to detect changes. Researchers report their findings in the Journal of Clinical .

Researchers followed 29 women—women whose body fat accumulated to the extent that it may have an adverse effect on health—of reproductive age for up to two years after Roux en Y gastric bariatric bypass surgery. Roux en Y is a procedure that creates a small pouch in the stomach that is directly connected to the midsection of the , bypassing the rest of the stomach and the upper portion of the small intestine.

Ovulation frequency and quality was determined by collecting daily urine specimens over the course of a menstrual cycle and measuring ovarian hormones. The researchers were surprised to find that ovulation rates remained high (more than 90 percent at all time points before surgery and at one, three, six, 12, and 24 months after surgery). The quality of the ovulation also remained unchanged, and there was little effect on the ovarian cycle.

The exception is a notable shortening of eight to nine days of the follicular phase. The follicular phase is the first half of the menstrual cycle, from the end of the previous menstrual flow until the release of the egg (ovulation). Three months after surgery, the phase is six and a half days shorter, and then up to nine days shorter by 24 months post-surgery.

Obesity is associated with longer menstrual cycles, specifically because of an increase in the follicular phase. The reason the phase shortens with is not yet known.

Sexual function at one year as detected by the Female Sexual Function Index, a self-reporting index of sexual health collected through questionnaires, is most noticeable. This improvement is independent of changes in hormone levels and body composition. and arousal increase the most. Researchers did not track sexual activity or desire to conceive. However, increased sexual desire may have led to increased frequency of sexual activity.

"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," Legro said. "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 ."

Explore further: Timing crucial in achieving pregnancy

Related Stories

Timing crucial in achieving pregnancy

September 3, 2012
A survey of women seeking fertility assistance to become pregnant found most did not know which days of the menstrual cycle they were fertile and most likely to conceive.

Weight loss surgery may be associated with increased substance use following surgery

October 15, 2012
Patients who undergo bariatric weight loss surgery may be at increased risk for substance use (drug use, alcohol use and cigarette smoking) following surgery, particularly among patients who undergo laparoscopic Roux-en-Y ...

Surgery-related weight loss in men reverses testosterone deficiency

June 4, 2011
Low testosterone levels and symptoms of male sexual dysfunction due to obesity may be reversible with weight loss after bariatric surgery, a new study finds.

Recommended for you

Shaming overweight kids only makes things worse

November 20, 2017
(HealthDay)—Overweight kids who are shamed or stigmatized are more likely to binge eat or isolate themselves than to make positive changes such as losing weight, a leading pediatricians' group says.

Link between obesity and cancer is not widely recognized

November 17, 2017
A new study published in the Journal of Public Health has shown that the majority of people in the United Kingdom do not understand the connection between weight issues and cancer. Obesity is associated with thirteen types ...

Reversing negative effects of maternal obesity

November 8, 2017
A drug that increases energy metabolism may lead to a new approach to prevent obesity in children born to overweight mothers, UNSW Sydney researchers have found.

Serving water with school lunches could prevent child, adult obesity: study

November 7, 2017
Encouraging children to drink plain water with their school lunches could prevent more than half a million youths in the U.S. from becoming overweight or obese, and trim the medical costs and indirect societal costs associated ...

Why do some obese people have 'healthier' fat tissue than others?

November 1, 2017
One little understood paradox in the study of obesity is that overweight people who break down fat at a high rate are less healthy than peers who store their fat more effectively.

Engineered protein treatment found to reduce obesity in mice, rats and primates

October 19, 2017
(Medical Xpress)—A team of researchers with pharmaceutical company Amgen Inc. report that an engineered version of a protein naturally found in the body caused test mice, rats and cynomolgus monkeys to lose weight. In their ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.