Clinical efficacy of Crinone on pregnancy outcomes in frozen embryo transfer: A retrospective study in the Chinese population.

Background: The aim of this study was to retrospectively investigate the effect of Crinone vaginal gel on pregnancy outcomes in women undergoing natural cycle (NC) frozen embryo transfer (FET) and to obtain the most suitable population for its routine application.

Methods: The 1613 women who underwent FET in the NC regimen [including the controlled ovulation stimulation protocol for the natural cycle, or the controlled ovulation stimulation protocol for the natural cycle (NC-COS)] from 2017 to 2021 were included. All patients were divided into 2 groups including Control group and Crinone group, which administered with or without Crinone vaginal gel. The key clinical information and between the 2 groups was recorded in detail.

Results: The results indicated that there were no statistical differences in blood β human chorionic gonadotropin (HCG) positive rate, clinical pregnancy, live birth, abortion (spontaneous and induced) and stillbirth between Control group and Crinone group. Moreover, Crinone could prevent spontaneous abortion. The spontaneous abortion rate in the Crinone group was 5.93% while this in control group was 8.32%. In the cohort exposed to Femoston, the preventive result was more significant (0/32 vs 5/15, P = .001). Furthermore, Crinone exhibited a significant protective effect on spontaneous abortion in 1520 patients who received no human menopausal gonadotropin (HMG) treatment.

Conclusion: This study demonstrated that the Crinone could protect women against spontaneous abortion, especially in patients who do not need HMG or in combination with Femoston.