GnRH agonist versus GnRH antagonist in ovarian stimulation: the influence of body mass index on in vitro fertilization outcome.

In an attempt to examine whether body mass index (BMI) may influence IVF outcome in patients undergoing COH with either GnRH-agonist (agonist group) or GnRH-antagonist (antagonist group), we studied 799 IVF cycles: 481 in the agonist group and 318 in the antagonist group. In patients with BMI >25 kg/m(2), COH with either GnRH-agonist or GnRH-antagonist achieved a comparable outcome; whereas in patients with BMI <25 kg/m(2), the use of GnRH-agonist suppressive protocol revealed significantly higher pregnancy rates.