Ovarian stimulation in women with high and low body mass index: GnRH agonist versus GnRH antagonist

This study evaluated women with a high body mass index (BMI) (>40 kg/m2) and low BMI (<18 kg/m2) undergoing assisted reproduction treatment and determined whether the type of gonadotrophin-releasing hormone (GnRH) analogue used has an impact on cycle parameters and outcome. The study analysed 65 women with high BMI and 118 with low BMI. In the former group, polycystic ovarian syndrome was significantly more prevalent in the agonist long protocol (ALP) group (P = 0.01) and gonadotrophin consumption was lower, peak oestradiol concentrations and total number of oocytes retrieved were higher in the ALP group compared with the antagonist (ANT) group. Implantation rate (IR), pregnancy rate (PR) per embryo transfer and early pregnancy loss rate (EPLR) were similar in both stimulation groups, with overall rates of 21.6%, 55.4% and 44.4%, respectively. In women with low BMI, peak oestradiol concentrations, total oocytes retrieved, mature oocytes and transferred embryos were higher in the ALP group compared with ANT group. IR, PR/embryo transfer and EPLR were similar in both groups, with overall rates of 24.3%, 52.5% and 16.1%, respectively. In all patients, no difference was found between ALP and ANT protocols concerning treatment outcome. Contrary to the reasonable EPLR observed in women with low BMI, the high rate found in women with high BMI is remarkable.