Research Information System
Journal of Assisted Reproduction and Genetics, vol.42, no.1, pp.221-229, 2025 (SCI-Expanded)
Purpose: To explore whether a 25 mg subcutaneous progesterone daily rescue daily improves the reproductive outcomes in patients with low serum progesterone (P4) levels (7–10 ng/mL), measured one day before true natural cycle (t-NC) frozen embryo transfer (FET). Methods: A cohort study of 192 women undergoing t-NC warmed blastocyst transfer. Patients were stratified into three different groups based on serum P4 levels on the FET-1 day: patients who had serum P4 levels of 7–10 ng/mL and underwent rescue progesterone administration (rescue group), patients with serum P4 levels of 7–10 ng/mL without progesterone administration (non-rescue group), and patients with serum P4 > 10 ng/mL on FET-1 day (control group). The primary outcome was possible differences in live birth rate (LBR) between groups. Results: The LBRs for the serum P4 7–10 ng/mL without rescue, 7–10 ng/mL with rescue, and > 10 ng/mL (control) groups were 41%, 46%, and 52%, respectively (p = 0.61). The estimated adjusted probability of live birth for serum P4 7–10 ng/mL without rescue, 7–10 ng/mL with rescue, and > 10 ng/mL (control) groups were also comparable: 43.5% (95% CI, 20.0–70.4%), 49.8% (95% CI, 28.1–71.6%), and 57.4% (95% CI, 44.0–69.8%), respectively. Conclusion: Serum P4 levels higher than 7 ng/mL seem to secure LBRs in patients undergoing t-NC FET. A rescue policy consisting of a daily subcutaneous 25 mg progesterone dose in patients with serum P4 levels 7–10 ng/mL does not further enhance LBRs when compared to those patients with similar serum P4 levels without rescue.