Impact of overweight and underweight on assisted reproduction treatment.

BACKGROUND Underweight and overweight may affect reproduction and interfere with treatment of infertility. The purpose of this report is to describe the independent effect of body weight on treatment with IVF and ICSI. METHODS Records of 5019 IVF or ICSI treatments in 2660 couples were reviewed. The influence of body mass index (BMI) on treatment outcome was examined, after accounting for differences in age and infertility diagnosis. RESULTS The cumulative live birth rate within three treatment cycles was 41.4% [95% confidence interval (CI) 32.1-50.7] in obese women with BMI > or =30 kg/m2 and 50.3 (95% CI 47.0-53.7) in normal weight women with BMI 18.5-24.9 kg/m2. Obesity was associated with an increased risk of early pregnancy loss occurring before 6 weeks gestation. Positive correlation between BMI and gonadotrophin requirement during stimulation and negative correlation between BMI and number of collected oocytes were observed. Underweight (BMI <18.5 kg/m2) was not related to an impaired outcome of IVF or ICSI. CONCLUSIONS Obesity is associated with lower chances for live birth after IVF and ICSI and with an impaired response to ovarian stimulation.