Researchers of a recent study have reported that fat women are more likely to miscarry a healthy baby and that women should try to lose weight before they conceive.

Inna Landres of Stanford University School of Medicine who led the study said, "The excess miscarriage rate in overweight and obese women is due to the loss of chromosomally normal embryos. It's important to identify elevated BMI [body mass index] as a risk factor for miscarriage and counsel those women who are affected on the importance of lifestyle modification."

The study by Stanford University School of Medicine in California found that women with a body mass index BMI of more than 25 were more likely to suffer a miscarriage as compared to lighter women. In the study researchers carried out a genetic analysis on 204 miscarriages on women with an average age of 35 years. They found that the 153 women who had a BMI of less than 25, 36.6 % had a miscarriage as compared to 52.9 % of the 51 women with a BMI of more than 25.

Mark Hamilton, chairman of the British Fertility Society who was not involved in the study, said, "This study will aid our understanding of the known association with being overweight and reproductive loss."

Dr Landres presented the results at the American Society for Reproductive Medicine conference in San Francisco said, "Obesity predisposes women to miscarry normal babies."

The suggestion is that the miscarriage in overweight women is not due to some abnormality with the fetus but more likely is a result of some other problem caused by the women being overweight. One possible cause is insulin resistance, the early stages of type II diabetes, which affects a woman's hormonal state.