Obesity may limit pregnancy chances

Obesity decreases the chances that a woman will get pregnant, and the more obese she is, the worse her prospects of conception, researchers said Tuesday.

Researchers at the Academic Medical Center in Amsterdam looked at how obesity affects women who are ovulating but having trouble with conception.

The study, published in the journal Human Reproduction, included more than 3,000 couples between 2002 and 2004 in 24 hospitals in the Netherlands.

Dr. Jan Willem van der Steeg and colleagues looked at the relationship between fertility in these women and their body mass index, a ratio of weight to height.

Women with a BMI of 30 or higher (i.e., obese) had significantly lower probability of becoming pregnant naturally, compared with women with BMIs of 21 to 29. One reason may be the hormone leptin, which regulates appetite and energy expenditure and is secreted in fatty tissues.