If you’re thinking about becoming pregnant or are struggling to get pregnant, here’s one more important reason to get to a healthy weight: New research is showing that obesity causes alterations in the ovaries of obese women that could stop an egg’s ability to make an embryo.

"Obesity is well known to cause changes in blood lipids and heightened inflammation, which detrimentally affects a person's general health," says Rebecca Robker, PhD, of Adelaide University in Australia. "Our research shows that obesity similarly changes the environment in the ovary, which bathes and nourishes a woman's developing eggs."

High levels of fat and inflammation around eggs in obese women could impair the egg’s development abilities, Dr. Robker says. Fats are known to alter egg metabolism, and inflammation can damage cells to the point that it affects embryo survival. In measuring hormone levels at an assisted reproductive clinic over the course of a year, researchers noted that obese women had altered ovaries associated with reproductive challenges.