Agonist versus antagonist protocol in induction of ovulation and its outcome

Prasad Lele, Raju Agarwal, Chuni Selden


Background: Gonadotropin-releasing hormone (GnRH) antagonist produces immediate suppression of gonadotrophins secretion without the initial stimulatory effect of premature luteinizing hormone (LH) .The aim of the study was to compare the agonist and the antagonist protocol in the induction of ovulation.

Methods: The study is a comparative study conducted from 01 November 2011 to 31 August 2013. All patients of primary or secondary infertility underwent a baseline transvaginal sonography on day 2 or day 3rd of the menstrual cycle for follicle count and endometrial thickness.  All patients received oral contraceptive pills from day 5 for 21 days of menstrual cycle and were assigned to two categories; the agonist and the antagonist group.

Results: A total of 380 patients, 190 patients of agonist group 52 had a positive β hCG (human chorionic gonadotropin) report (27.3%) compared to the 60 patients of 190 antagonist group (31.5%). The P value was 0.44 which is statistically insignificant. Age group were similar and mean age of agonist group was27.96+3.21 where as in antagonist group 28.11+3.24. The number of oocyte retrieved was found to be better in the antagonist group compared to agonist group (mean±sd 10.71+6.41 versus 8.62±5.65, P value<0.001). The patients in the agonist group had a slightly more number of transfers performed (2.78±0.94), in comparison to the antagonist group (2.75±0.97). P-value was 0.789 which was statistically insignificant.

Conclusions: The GnRH antagonist therefore seems to be a more patient friendly protocol for the first choice in ART cycle with lower incidence of side effects and similar pregnancy rate. It is also time saving and simple protocol with good clinical outcome.


GnRH antagonist, Agonist, LH, FSH, hCG, Endometrium thickness

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