Body mass index and risk of miscarriage in women with recurrent miscarriage

Objective: To investigate the effect of underweight, overweight, and obesity on the risk of miscarriage in the subsequent pregnancy in women with recurrent miscarriage. Design: Retrospective analysis of prospectively collected data from the database of a tertiary recurrent miscarriage center. Setting: The recurrent miscarriage clinic at Sheffield Teaching Hospitals. Patient(s): A total of 844 pregnancies from 491 patients with recurrent miscarriage were included in the analysis. Main Outcome Measure(s): The odds of miscarriage in the subsequent pregnancy for all pregnancies after referral to the recurrent miscarriage clinic as well as the first pregnancy post referral. Result(s): When analyzing all pregnancies, and compared to women with a normal body mass index, obese and underweight patients had a significantly higher odds of miscarriage in the subsequent pregnancy (OR, 1.71; 95% CI, 1.05-2.8; and OR, 3.98; 95% CI, 1.06-14.92; respectively), whereas there was no significantly increased odds of miscarriage in overweight women (OR, 1.02; 95% CI, 0.72-1.45). Logistic regression analysis showed that the most important factor predicting the occurrence of miscarriage was advanced maternal age (P = 0.01) followed by an increased body mass index (P = 0.04). Conclusion(s): In women with recurrent miscarriage, a mild increase in the body mass index does not increase the risk of miscarriage, whereas obese and underweight patients have a small but significant increased risk of miscarriage in the subsequent pregnancy. (Fertil Steril (R) 2010; 94: 290-5. (C) 2010 by American Society for Reproductive Medicine.)