Female Weight and Fertility
Adapted from a presentation by Dr. Jose Bellver from the Instituto Valenciano de Infertilidad in Valencia, Spain.
Many studies have shown that increased female weight can negatively affect the chances of success from IVF treatment. Until now, it has not been clear whether this increased weight impacted on the quality of one’s eggs, the receptivity of the uterus, or both.
A large study of almost 10,000 cycles of DONOR egg In Vitro Fertilization was recently (July 2013) presented at an annual meeting of the European Society of Human Reproduction and Embryology in London. Since all the egg donors in this study were of normal weight, their body mass did not confound the results, and the study outcome reflected only the impact of the egg recipients’ varying body weight on the probability of success (= uterine receptivity).
The recipients of the donor eggs were divided into four groups: lean with BMI of 19.9 or less, normal with BMI 20-24.9, overweight with BMI 25-29.9, and obese with BMI of 30 or more.
When the outcome of the treatment was cross-checked against the BMI of the egg recipient, results showed that the rates of embryo implantation and the probability of a live birth were reduced with each BMI increase.
For example, live birth rate in the four groups was 38.6% in the lean, 37.9% in the normal weight, 34.9% in the overweight, and 27.7% in the obese. Similarly, the rate of embryo implantation in the uterus was 40.4% in the lean, 39.9% in the normal weight, 38.5% in the overweight, and 30.9% in the obese. These trends translated to a statistically significant 27% lower risk of live birth for an obese patient than for one of normal weight.
The results of this study confirm that control of excess weight, especially through lifestyle interventions, should be an integral part of reproductive treatments.