Research published today in the October issue of Obstetrics & Gynecology found that women who exercised four or more hours per week–and had done so for the previous one to nine years–were 40 percent less likely to have a baby after their first IVF treatment than if they hadn’t exercised. Surprisingly, however, women who had followed a rigorous fitness regimen for 10 to 30 years were just as likely to end up with a baby as women who didn’t exercise.

Excessive exercise can stress a woman’s reproductive system, causing her body to “protect” it from a pregnancy it’s not prepared to maintain–perhaps by causing subtle hormonal changes, theorizes Mark Hornstein, senior researcher and clinical director of reproductive endocrinology at Brigham and Women’s Hospital in Boston. Why does the effect seem to wear off after 10 years? “We don’t have a good answer for that,” says Hornstein. “It may be that the body accommodates.”


This article does not say that it is impossible for women that have recently become phsically fit to become pregnant through IVF. Using information from this article, potential parents can discuss any changes they can make with their doctor.