High progesterone levels before frozen embryo transfer do not compromise reproductive outcomes

Elevated serum progesterone levels before frozen embryo transfer (FET) in artificially prepared cycles with vaginal or vaginal plus subcutaneous progesterone have no negative impact on reproductive outcomes, as reported in a study.

Researchers looked at a total of 3,183 FET cycles under hormonal replacement therapy. A total of 1,360 cycles corresponded to frozen homologous embryo transfer (hom-FET), 1,024 were euploid ET (eu-FET) after preimplantation genetic testing for aneuploidies (PGT-A), and 799 cycles were frozen heterologous ET (het-FET).

Luteal phase was covered using 200 mg/8 h of vaginal micronized progesterone either alone or in combination with a daily subcutaneous injection of 25 mg of progesterone.

There were 1,360 cycles that corresponded to frozen homologous embryo transfer (ET). All women had adequate serum progesterone levels (≥10.6 ng/ml) before the procedure (median, 14.39 ng/ml). Progesterone levels were significantly higher in the group under vaginal plus subcutaneous progesterone vs vaginal progesterone (15.96 vs 14.09; p<0.001).

Clinical pregnancy, miscarriage, and live birth rates did not differ by the use of vaginal or vaginal plus subcutaneous progesterone for each of the following groups: hom-FET, eu-FET, and het-FET). Live birth rates were similar among patients in the highest centile of serum progesterone levels (22.33 ng/ml) and the rest of the women (43.9 percent vs 41.3 percent; p=0.381).

Those with progesterone levels ≥p90 had lower body mass index than women with lower progesterone levels (<p90; 22.62 vs 23.32; p=0.009). Analysis that grouped the women in deciles according to serum progesterone levels showed no differences in live birth rates (p=0.938).