Progesterone protocol versus gonadotropin-releasing hormone antagonist protocol in women with polycystic ovarian syndrome undergoing fertilization treatments with frozen-thawed embryo transfer: a prospective randomized controlled trial.

Background: Exogenous progestational agents have recently been introduced as an alternative pituitary modulator for the prevention of premature luteinizing hormone (LH) surges during in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatments. There is increasing evidence that frozen-embryo transfer (FET) is associated with a lower risk of ovarian hyperstimulation syndrome (OHSS) in women with polycystic ovary syndrome (PCOS). Herein, we compared the clinical outcomes of the progesterone protocol with the gonadotropin releasing hormone antagonist (GnRH-ant) protocol in PCOS patients with a ''freeze-all'' strategy.

Methods: In this prospective single-central randomized controlled trial, a total of 120 PCOS patients undergoing their first IVF/ICSI treatment were randomly assigned to receive the progesterone protocol (study group) or GnRH-ant protocol (control group). The main outcome was the number of oocytes retrieved. Secondary outcomes included the incidence of premature LH rise/surge, the number of viable embryos, and pregnancy outcomes.

Results: The number of retrieved oocytes (14.65±7.64 versus 12.8±8.57) and viable embryos (5.38±3.54 versus 5.03±3.92) in the study group were comparable to those in the control group (P>0.05). Similarly, no between-group differences were found in the number of mature oocytes, fertilized oocytes, cleaved embryos, and the viable embryo rate per oocyte retrieved (P>0.05). However, the oocyte retrieval rate (66.02%±19.63% versus 54.38%±26.39%) and fertilization rate (78.12%±18.41% versus 62.76%±23.32%) in the study group were significantly more than that in the control group (P<0.05). The mean serum LH value on day 6-7 was lower in the study group than that in the control group (7.47±0.97 versus 3.98±0.52 IU/L, P<0.05), and the incidence of premature LH rise was higher in the study group than in the control group, although no patients experienced premature LH surge. The clinical pregnancy rate [58.82% 57.32%, RR 0.94 (95% CI: 0.508, 1.738), P>0.05] and implantation rate [43.21% 41.4%, RR 0.929 (95% CI: 0.595, 1.448), P>0.05] were also similar between the two groups.

Conclusions: The progesterone protocol is comparable with the GnRH-ant protocol regarding oocyte/embryo yields and the probability of clinical pregnancy in PCOS patients, but the two regimens were distinct in the regulation of pituitary LH secretion.

Trial Registration Number: Chictr.org.cn: ChiCTR-IOR-15006633.