Increased body mass index has a deleterious effect on in vitro fertilization outcome

Purpose: Few studies have addressed the effect of weight on IVF outcome, with some showing a decrease in IVF success and some showing no change in overweight women (BMI > 25 kg/m²) compared to women with normal weight (BMI < 25 kg/m²).Methods: One hundred thirty-nine women <40 years old undergoing 180 IVF cycles with fresh embryo transfers were retrospectively evaluated between January 1997 and March 1999, stratified by body mass index (BMI) (cutoff of 25).Results: In the group with BMI > 25 kg/m², basal FSH, implantation rates (IR), and pregnancy rates (PR) were significantly lower, while the duration of stimulation, gonadotropin requirements, and spontaneous miscarriages were slightly higher, compared to the BMI 25 group.Conclusions: Excess weight defined as BMI > 25 kg/m² has a negative impact on IVF outcome. Future prospective studies evaluating oocyte and/or embryo quality, and androgen and insulin levels, between overweight women and those with normal weight are needed.