There can be too much of a good thing when it comes to this common fertility hormone, according to a new study.

By Melissa Willets
November 30, 2015
in vitro fertilization
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A new study out of Michigan State University found, contrary to commonly held belief, that women given too much follicle stimulating hormone, or FSH, during IVF are actually less likely to have a baby. Published in the journal Fertility and Sterility, this is the largest study yet to link too much FSH with a lower rate of live births.

FSH is typically given to women undergoing IVF to stimulate as many follicles as possible in the ovaries so multiple eggs can be recovered for fertilization. But researchers looked at data from 650,000 IVF cycles of women across the country and determined there can be too much of a good thing.

"The study answers the question of whether or not more FSH is detrimental to the survival of the embryo. As the dosage of FSH increased, live birth rates decreased by as much as 15 to 20 percent," explains study co-author James Ireland, a reproductive physiology professor at MSU.

The relationship between too much FSH and declining live births held true no matter a woman's age, weight, or how long she'd been undergoing fertility treatments.

Ireland said the goal of the study was to help determine the right amounts of FSH needed to support a healthy pregnancy and baby. Ultimately, he added, fertility doctors should be more aware of these effects, and strive to avoid giving their patients higher amounts of the hormone.

Melissa Willets is a writer/blogger and a mom. Follow her on Twitter (@Spitupnsuburbs), where she chronicles her love of exercising and drinking coffee, but never simultaneously.