BACKGROUND

Obesity has been identified as a risk factor for spontaneous miscarriage although the mechanism is unclear. The purpose of this study is to better understand the effect of obesity on early pregnancy success by examining the cytogenetic results of miscarriages in women with normal and elevated body mass index (BMI).

METHODS

We conducted a retrospective case–control study in an academic infertility practice. Medical records of women ages <40 years with first trimester missed abortion (n = 204), who underwent dilatation and curettage between 1999 and 2008, were reviewed for demographics, BMI, diagnosis of polycystic ovary syndrome (PCOS) and karyotype analysis. ² and Student's t-test analysis were used for statistical analysis, with P < 0.05 considered significant.

RESULTS

A total of 204 miscarriages were included, from women with a mean age of 34.5 years. The overall rate of aneuploidy was 59%. Women with BMI ≥ 25 kg/m² had a significant increase in euploid miscarriages compared with women with lower BMI (P = 0.04), despite a similar mean age (34.4 years for both).

CONCLUSIONS

We found a significant increase in normal embryonic karyotypes in the miscarriages of overweight and obese women (BMI ≥ 25). These results suggest that the excess risk of miscarriages in the overweight and obese population is independent of embryonic aneuploidy. Further studies are needed to assess the impact of lifestyle modification, insulin resistance and PCOS on pregnancy outcomes in the overweight and obese population.