NEW YORK (Reuters Health) - Preliminary findings from patients who underwent obesity surgery, also known as bariatric surgery, at Washington University in St. Louis, indicate that this procedure used to induce weight loss may improve the ability of morbidly obese women to conceive after undergoing in vitro fertilization (IVF).
Meanwhile, a second study conducted at Albert Einstein College of Medicine in Bronx, New York, suggests that reproductive hormone levels are reduced in obese women and are only partially restored to normal within 6 months following weight-reduction surgery.
Both studies were presented Tuesday at the 64th annual meeting of the American Society for Reproductive Medicine in San Francisco.
“Some studies have shown that women who are obese and undergoing fertility treatment have less success, require higher doses of medication to help get them to ovulate, as well as higher miscarriage rates,” Washington University’s Dr. Beth M. Lewkowski said in an interview with Reuters Health. As a result, “a lot of centers will advocate that obese women attempt to lose weight before considering fertility treatment.”
Lewkowski’s team reviewed the records of five obese women who underwent bariatric surgery followed by IVF. Currently, three of the women have delivered healthy full-term infants, Lewkowski said, and the other two women are still pregnant.
All five women had been infertile for 2 to 10 years before bariatric surgery. Three of the women became pregnant after one IVF cycle; their body mass index at the time of IVF ranged from 22.8 to 29.9. The other two women underwent three IVF cycles before they conceived. The body mass index during the first cycle was higher, at 36 and 39.2.
Body mass index(BMI) is the ratio of weight to height. A normal BMI ranges from 18.5 to 24.9.
Despite these outcomes, Lewkowski commented, adding infertility as a reason for bariatric surgery is something that requires more research before such a recommendation can be made.
In the second presentation, the Einstein team led by Dr. Alex J. Polosky discussed how morbid obesity affects follicle stimulating hormone, inhibin, and Mullerian inhibiting substance (MIS).
“Obesity leads to decreased fertility in women with irregular and regular menstrual periods alike,” Polosky told Reuters Health. “However, weight loss only partially reverses reduced fertility; and we don’t know why.”
They studied seven morbidly obese women (with an average body mass index of 49) who underwent bariatric surgery, leading to an average BMI of 37 at 6 months after surgery, along with 36 normal-weight infertile women who had normal ovarian reserve.
At the start of the study, the obese women had levels of follicular stimulating hormone and inhibin B (an ovarian hormone) that were significantly lower than in normal-weight women.
The 25 percent average weight loss was associated with significant recovery of follicular stimulating hormone levels, but not of inhibin B. MIS, a measure of ovarian reserve, did not differ significantly between normal and obese subjects.
“Our data suggest that morbidly obese women do not produce enough follicular stimulatory hormone from their pituitary gland to make the ovary function properly,” Polotsky noted. “Inhibition of follicular stimulatory hormone secretion via inhibin B was lower than expected. Yet, despite this inhibitory hormone being low, follicular stimulatory hormone did not rise.”
Polotsky concluded: “This apparent deficit in follicular stimulatory hormone responsiveness in obese women is incongruous with their apparently normal ovarian reserve,” as indicated by MIS levels. “These data imply that in a morbidly obese woman either the brain is not sensing the ovarian hormone signal (inhibin), or the ovarian hormone signal is not working properly.”
Polotsky’s group is now planning studies in which they will block the normal hormonal feedback from the ovary more completely and examine how the pituitary gland responds.