Using Letrozole Cotreatment With Progestin-Primed Ovarian Stimulation In Women With Polycystic Ovary Syndrome Treated For IVF

Abstract Background: Women with polycystic ovary syndrome (PCOS) often experience poor oocyte quality and a high risk of ovarian hyperstimulation syndrome (OHSS) when treated with controlled ovarian stimulation (COS) in vitro fertilization (IVF). Progestin-primed ovarian stimulation (PPOS) shows good potential to compete with conventional protocols in women with PCOS. However, it always accompanied by increased pituitary suppression and gonadotropin consumption. Letrozole (LE) has the ability to increase luteinizing hormone (LH) levels and appears to have the potential to alleviate pituitary inhibition during COS in women with PCOS. A retrospective cohort trial was performed to evaluate the efficacy of PPOS with or without letrozole in infertile women with PCOS.Methods: This retrospective cohort study included 448 women with PCOS who underwent COS with human menopausal gonadotropin (hMG) and medroxyprogesterone acetate (MPA) (n=224) or hMG and MPA cotreatment with LE (n=224) from January 2018 to March 2021. Baseline characteristics of the two groups were balanced with propensity score matching using the nearest neighbour random matching algorithm at a ratio of 1:1. The primary outcome measure was the implantation rate. The secondary outcomes were the endocrinological profiles, gonadotropin dose and duration, number of oocytes retrieved and viable embryos, clinical pregnancy rate, miscarriage rate and ectopic pregnancy rates.Result(s): The implantation rate was significantly higher in the study group than that in the control group (42.22% vs. 34.69%, P < 0.05). Compared with the control group，the study group had a higher LH concentration on the trigger day (3.85±3.6 mIU/ml vs. 2.44±1.71 mIU/ml, P < 0.01), but there was no case of premature LH surge or OHSS in both groups. The consumption of gonadotropin, the number of oocytes retrieved and viable embryos were similar between the two groups. Additionally, no difference was found in the clinical pregnancy rate, miscarriage rate or ectopic pregnancy rate.Conclusion(s): This study shows that LE administration in the PPOS protocol was feasible to improve the implantation rate and alleviate profound pituitary suppression from progestin administration without interfering with its premature LH surge blockade effect but with a non-significant reduction in gonadotropin consumption in women with PCOS undergoing IVF treatment.