GnRH antagonist versus agonist in normoresponders undergoing ICSI: a randomized clinical trial in Iran

Abstract Background: General concern is that the pregnancy rate is higher with GnRH-agonist as a protocol of pituitary suppression. GnRH-antagonist protocol provides a shorter period of administration and an easy flexible protocol. Objective: In this study, the outcomes of GnRH agonist and antagonist in ICSI cycles are compared in normo responder patients. Materials and Methods: In this randomized clinical trial, 300 normoresponders undergoing ICSI were randomly divided to GnRh agonist (n=150) and GnRh antagonist (n=150) groups. The main outcome measurements were chemical, clinical and ongoing pregnancy rates (PR). Results: The mean duration of stimulation were 9.6±1.6 and 8.2±1.6 days in agonist and antagonist groups respectively (p=0.001). The mean number of MII oocyte retrieved in agonist and antagonist groups were 7.7±4.0 and 6.9±4.3 respectively (p=0.03). There was no significant difference between two groups regarding mean number of gonadotrophin ampoules, follicles, occytes, total embryos and good quality embryos, OHSS incidence, and abortion rate. Chemical pregnancy rate was 35.3% in agonist and 39.3% in antagonist group. Clinical pregnancy rate was 35.3% in agonist and 34% in antagonist group. Ongoing pregnancy rate was 45 (31.3%) in agonist and 44 (29.3%) in antagonist group. There was no significant difference between two groups in pregnancy rates. Conclusion: In this study antagonist protocol was shown to be an easy, safe and friendly protocol in Iranian normoresponder patients, having similar outcomes with standard agonist protocol but shorter period of stimulation.