Oral dydrogesterone versus oral dydrogesterone plus micronized vaginal progesterone for luteal phase support in ovulatory frozen-thawed embryo transfers.

RESEARCH QUESTION

Is oral dydrogesterone (DYD) alone as effective as DYD + micronized vaginal progesterone (MVP) for luteal phase support (LPS) in ovulatory frozen-thawed embryo transfer (FET) cycles?

DESIGN

This retrospective cohort study included 22,868 patients undergoing their first FET cycles using an ovulatory protocol between January 2011 and February 2023. Patients were classified into two cohorts according to LPS protocol: oral DYD alone or DYD + MVP. After propensity score matching (PSM), pregnancy and neonatal outcomes were compared to determine the efficacy and safety of oral DYD alone. Further stratification was made to observe the effect of oral DYD alone for each endometrial preparation regimen (natural, letrozole or human menopausal gonadotrophin). Logistic regression and stratified analysis based on maternal age further confirmed the results before PSM.

RESULTS

After PSM, there were 6153 patients in the oral DYD group and 6153 patients in the DYD + MVP group. No significant differences in the clinical pregnancy rate (CPR) (51.8% versus 52.2%, P = 0.626), live birth rate (LBR) (42.8% versus 43.2%, P = 0.623), miscarriage rate (P = 0.637) and other pregnancy outcomes were observed between the two cohorts. These results were reconfirmed for each endometrial preparation protocol. No significant differences in newborn sex, birth weight or birth defects were found between the two cohorts (P > 0.05). Regression analysis showed no influence of LPS protocol on CPR (P = 0.672). Stratified analysis showed no impact of LPS protocol on CPR, LBR or miscarriage rate in patients aged <35 years and patients aged ≥35 years.

CONCLUSIONS

Oral DYD alone is comparable to DYD + MVP for LPS in ovulatory FET cycles in terms of pregnancy and neonatal outcomes.