Effects of female increased body mass index on in vitro fertilization cycles outcome

As being overweight can impair female spontaneous fertility or after assisted reproductive technology (ART) cycles, the aim of this study was to compare in vitro fertilization (IVF) outcome according to women's body mass index (BMI).

Retrospective study conducted from 2006 to 2009 in the IVF unit of Nantes University Hospital, France. 582 patients undergoing standard infertility workup and controlled ovarian stimulation were categorized according to BMI into two groups: group 1: normal weight (20-24.9 kg/m(2); n=409) and group 2: overweight and obese (≥25 kg/m(2); n=149). Basal hormonal status, smoking habitus, infertility duration, IVF cycle parameters and outcome were recorded.

Basal LH, FSH and estradiol levels were higher in group 1 than group 2, but ovarian reserve markers were comparable across the two BMI groups. Higher doses of gonadotropins were required in group 2 to obtain equivalent ovarian response than in group 1. No difference was observed on ovarian response and embryonic parameters. Cycle outcome were not significantly different between both groups, but we found a strong trend towards increasing transfer cancellation and miscarriage rates in group 2.

Although overweight and obesity do not compromise ovarian stimulation results whenever adaptation of recombinant FSH doses is made, our data suggest an increased risk of cancellation transfer and miscarriage rate, leading to poorer IVF outcome.