Outcome Using Oral Dydrogesterone versus Intravaginal Micronized Progesterone Gel in Hormone Replacement Treatment Frozen Embryo Transfer Cycle: A Retrospective Analysis

Abstract Background: The aim of this study was to analyze the clinical outcomes between oral dydrogesterone and intravaginal micronized progesterone gel in HRT-FET cycles. Methods: A retrospective cohort study based on totally 344 HRT-FET cycles without GnRHa agonist pretreatment was conducted. All the cycles were allocated to two groups in the reproductive medical center at the University of Hong Kong-Shenzhen hospital. One group of HRT-FET cycles (n=193) used oral dydrogesterone before the embryo transfer, the other group (n=151) used intravaginal micronized progesterone gel. Results: There was no significant difference in women’s age, BMI, antral follicle count, number of embryos transferred, serum estradiol and progesterone levels on day 2 of the menstrual cycle and on the day before endometrial transformation, and the endometrial thickness on the day 2 of the menstrual cycle and the day before endometrial transformation between the two groups. There was significant difference in biochemical pregnancy rate between the two groups (P=0.02). And no significant difference were found in clinical pregnancy rate, LBR, embryo implantation rate, ectopic pregnancy rate, and neonatal weight between the two groups. In the multivariate logistic regression analysis for covariates, the different luteal support medication did not have a significant positive association with the LBR. In Conclusion, Conclusion: The study found no significant difference in LBR between oral dydrogesterone and intravaginal micronized progesterone gel in HRT-FET cycles. And the single administration of oral dydrogesterone could be a new option in HRT-FET treatment.