SUNDAY DEC 16, 2007 (Foodconsumer.org) -- Obesity worsens a woman's prospect of conception and reduces her chances of getting pregnant significantly, according to a study published by Dutch researchers in the journal Human Reproduction.

The study of more than 3,000 couples who were followed up between 2002 and 2004 in 24 hospitals in the Netherlands found women who had a body mass index above 30 (defined as obese) were significantly less likely to get pregnant.

Those with their BMI at 35 were 26 percent less likely to become pregnant whereas those with MI at 40 had their odds of getting pregnant reduced by 43 percent.

Dr. Jan Willem van der Steeg and colleagues at the Academic Medical Center in Amsterdam suggested that a hormone known as leptin may play a role in the reduced fertility in obese women.

But the study has a number of limitations including the fact that the researchers did not track the timing and frequency of sexual intercourse, which is relevant because they affect the likelihood.   For example, early research reported that obese women have sex less frequently than women with normal weight.