GnRH antagonist protocol is associated with elevated levels of nitric oxide and a reduced pregnancy rate in IVF cycles

The study was designed to determine the nitric oxide (NO) levels in IVF/ICSI cycles subsequent to GnRH antagonist and GnRH agonist treatment and to explain the difference of pregnancy rate between these protocols. A prospective, randomized controlled study was performed with 20 patients treated with cetrorelix and 37 patients with buserelin. Serum and follicular levels of NO was determined with chemiluence method. The patients underwent the protocol with cetrorelix had less number of follicles (11.8±4.7 vs. 14.5±5.5, p=0.033) and lower pregnancy rate (25% vs. 56.8%, p=0.022), together with higher levels of serum NO (p=0.008). The follicular levels of NO were associated with fragmentation degree of embryos (p=0.030) in IVF cycles. We conclude that the GnRH antagonist protocol is associated with elevated levels of NO and a reduced pregnancy rate noted in IVF cycles. Elevated follicular levels of NO are associated with poor embryo quality.