A woman's weight influences her fertility, two new studies suggest.
In one study, researchers compared Society for Assisted Reproductive Technology (SART) data on 158,385 menstrual cycles with the height and weight of women.
They found that cycle cancellation rates became more common with increasing body mass index (BMI) and that the chances of not becoming pregnant, or failing to carry a pregnancy to term, rose significantly with increasing obesity.
In the other study, researchers at Harvard University and Brigham and Women's Hospital in Boston examined the quality of eggs and embryos from women with different BMIs.
Eggs from women with high and low BMIs were more likely than eggs from normal-weight women to produce immature oocytes during an assisted reproductive technology (ART) cycle, leading to a lower likelihood of successful embryo transfer and a lower live birth rate.
"Clearly a healthy body weight is an important advantage in all aspects of health, including reproductive health," Dr. James Goldfarb, SART president, said in an American Society for Reproductive Medicine news release.
"We are hoping that with better information we can provide better help to our patients whose struggle with infertility includes a struggle with weight," he said.