Frozen-thawed embryo transfer: does the addition of low-dose choriogonadotropin alfa to progesterone in the luteal phase of artificial cycles improve the endometrium and increase the chances of pregnancy?

Objective: Primary: To evaluate the effect of low doses of recombinant hCG (choriogonadotropin alfa) in the luteal phase of frozen-thawed embryo transfers (FET) of artificial cycles on the chances of pregnancy in patients aged ≤38years. Secondary: To assess the chances of pregnancy in the FET groups of artificial cycles using micronized vaginal progesterone (VP) versus injectable intramuscular progesterone (IMP) and the chances of pregnancy in type-1 embryo transfers (two top embryos).

Methods: This retrospective cohort study included 122 cycles of FET and compared two groups of patients aged 38 years or younger, one given hCG in the luteal phase and one not administered hCG.