Body mass index and short-term weight change in relation to treatment outcomes in women undergoing assisted reproduction

Objective: To assess the relation between body mass index (BMI) and short-term weight change with assisted reproductive technology (ART) outcomes. Design: Prospective cohort study. Setting: Fertility center. Patient(s): A total of 170 women undergoing 233 ART cycles. Intervention(s): Baseline BMI and short-term weight change were related to ART outcomes. Regression models accounting for repeated observations were used to adjust data for potential confounders. Main Outcome Measure(s): Peak E2 levels, oocyte yield, MII yield, fertilization rate, embryo quality, postive [beta]-hCH, clinical pregnancy and live birth rates. Result(s): Overweight and obesity were associated with lower live birth rates. The adjusted live birth rate (95% confidence interval) was 42% (28%-58%) among women with a BMI between 20 and 22.4 kg/m(2) and 23% (14%-36%) among overweight or obese women. Short-term weight loss was associated with a higher proportion of metaphase II (MII) oocytes retrieved. The adjusted proportion of MII eggs was 91% (87%-94%) for women who lost 3 kg or more and 86% (81%-89%) for women whose weight remained stable. This association was stronger among women who were overweight or obese at baseline. Short-term weight loss was unrelated to positive beta-hCG, clinical pregnancy, or live birth rates. Conclusion(s): Overweight and obesity were related to lower live birth rates in women undergoing ART. Short-term weight loss was related to higher MII yield, particularly among overweight and obese women, but unrelated to clinical outcomes. (Fertil Steril (R) 2012. (C) 2012 by American Society for Reproductive Medicine.)