Elevated serum progesterone levels before frozen embryo transfer do not negatively impact reproductive outcomes: a large retrospective cohort study

Objective: To evaluate whether patients with high-serum progesterone levels before frozen embryo transfer (FET) under hormonal replacement therapy present with worse reproductive outcomes. Design: A cohort retrospective study. Setting: A university-affiliated fertility center. Patient(s): A total of 3,183 FET cycles in patients receiving hormonal replacement therapy between March 2009 and December 2020 were included. The luteal phase was covered with 200 mg per 8 hours of vaginal micronized progesterone either alone or in combination with a daily subcutaneous injection of 25 mg of progesterone. A total of 1,360 cycles corresponded to frozen homologous embryo transfer (ET) (hom-FET), 1,024 were euploid ET (eu-FET) after preimplantation genetic testing for aneuploidies, and 799 cycles were frozen heterologous ET (het-FET). All patients had adequate serum progesterone levels (R10.6 ng/mL) before the procedure. Intervention(s): Frozen embryo transfer cycles. Main Outcome Measure(s): Clinical pregnancy, miscarriage, and live birth rates (LBRs). Results: Median (P25; P75) serum progesterone level before FET was 14.39 (12.43-17.49) ng/mL. Progesterone levels were significantly higher in the group under vaginal plus subcutaneous progesterone (15.96 [13.74-21.60] vs. 14.09 [12.19-16.95]). No differences in clinical pregnancy, miscarriage, and LBR were observed based on the use of vaginal or vaginal plus subcutaneous progesterone for each of the groups (hom-FET, eu-FET, and het-FET). Live birth rates were comparable among patients in the highest centile of serum progesterone levels (>= p90) (22.33 ng/mL) and the rest of the patients (p< 90) (43.9% vs. 41.3%). Patients with progesterone levelsRp90 presented lower body mass index than those in the lower centiles (

Automated summary

This study evaluated the reproductive outcomes of patients with high-serum progesterone levels before frozen embryo transfer (FET) under hormonal replacement therapy. The results showed no significant differences in clinical pregnancy, miscarriage, and live birth rates between the use of vaginal progesterone alone or in combination with subcutaneous progesterone for FET in different types of embryo transfers. The live birth rates were comparable between patients with high-serum progesterone levels and the rest of the patients.