High BMI may up risk of miscarriage.(News)

San Francisco -- The risk of miscarriage of a genetically normal fetus is significantly increased in overweight women, compared with normal weight women, the findings of a retrospective case-control study of 204 miscarriages suggest.

The rate of euploid miscarriage among 204 first-trimester missed abortions that occurred between 1999 and 2008 in women at a single center was 53% in those with a body mass index of 25 or greater, compared with 37% in those with a BMI of less than 25. The difference was statistically significant, Dr. Innes V Landres reported at the annual meeting of the American Society for Reproductive Medicine.

The mean age of the women in both groups was the same (34 years). Those over age 39 years were excluded because of the increased risk of miscarriage in women with advanced maternal age, noted Dr. Landres, a chief resident in obstetrics and gynecology at Stanford (Calif.) University.

The groups also were similar in regard to types of assisted reproductive technologies used and pregnancy history.

The study was undertaken to explore the cytogenetic results of miscarriages in relation to maternal weight and insulin resistance, Dr. Landres explained.

Both obesity and insulin resistance have been linked with spontaneous abortion and recurrent pregnancy loss. Most spontaneous abortions are a result of fetal aneuploidy, as was the case in 59% of patients overall in this study--67% in those over age 34 years, and 50% in those 34 years and younger. There is some evidence, however, that obesity predisposes women to euploid miscarriage, and that there is an increased rate of spontaneous abortion even among obese women with ovum donation.

For the current study, the medical records of women with first-trimester missed abortion, subsequent dilation and curettage, and karyotype analysis of the ...