The great weight debate: do elevations in body mass index (BMI) exert a negative extraovarian effect on in vitro fertilization outcome?

There is an increasing body of evidence that excess weight is associated with decreased pregnancy rates, lower birth rates, lower implantation rates, and the possibility of decreased follicle development and oocyte numbers as well as an increased gonadotropin requirement in patients undergoing in vitro fertilization or intracytoplasmic sperm injection. Whether the mechanism is ovarian, endometrial, or a combination of the two is unknown.