Early initiation of gonadotropin-releasing hormone antagonist in polycystic ovarian syndrome patients undergoing assisted reproduction: randomized controlled trial ISRCTN69937179

To compare the implantation rates in two groups of women with Polycystic Ovary Syndrome (PCOS) after embryo transfer based on the initiation time of GnRH antagonist. Secondary outcome measures included clinical pregnancy, delivery and miscarriage rates. This is a prospective, randomized trial in which 140 PCOS patients underwent ICSI, with 122 having ET performed. GnRH-antagonist was started on day 1 of stimulation in 69 patients (Group 1) or day 5 in 71 patients (Group 2). The overall implantation rate in Group 1 (46.2 %) was clinically higher than Group 2 (35.5 %), although not statistically significant (p = 0.075). For blastocysts transfer, the implantation rate in Group 1 was 55.1 %, compared to 40.4 % in Group 2 (p = 0.051). There was a clinically, but not statistically, higher clinical pregnancy rate (68.3 % vs. 56.5 %) and delivery rate (60.0 % vs. 53.2 %) per transfer in Group 1 compared to Group 2, respectively. There was a statistically significant lower biochemical pregnancy rate in Group 1 (2.4 %) compared to Group 2 (18.6 %) [p = 0.015]. There was no difference in miscarriage rates between the two groups. Our data suggest that early initiation of GnRH antagonist on day 1 of ovarian stimulation in PCOS patients undergoing ICSI-ET may improve implantation rates, especially after blastocyst transfer.