The study will be published in Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM).

Fat women who try to become pregnant experience longer times to conception, even if they are young and have a regular menstrual cycle. This study sought to determine if there are alterations in an egg’s environment in obese women which contribute to poorer reproductive outcomes.

"Characteristics of eggs are influenced by the environment in which they develop within the ovary," said Dr Rebecca Robker, PhD, of Adelaide University in Australia and lead author of the study.

"Our study found that obese women have abnormally high levels of fats and inflammation in the fluid surrounding their eggs which can impact an egg’s developmental potential,” the expert added.

The fats might alter the very sensitive metabolism of the egg and such changes are known to be harmful to embryo formation, Robker said.

In addition, inflammation can damage cells and when this happens to eggs it can affect embryo survival.

To reach the conclusion, researchers followed 96 women seeking assisted reproduction at a private clinic in South Australia from February 2006 to April 2007. Robker and her colleagues measured hormone and metabolite levels in follicular fluid obtained from the subjects'' ovaries during their egg collection procedures.