Progesterone Levels and Clinical Outcomes Using a Single Pessary of 400 mg of Vaginal Progesterone in Substitutive Cycles for Embryo Transfer.

This study aims to compare the efficacy, in terms of progesterone levels and clinical outcomes, of two different presentations of micronized vaginal progesterone (400 mg vs. 200 mg) used in endometrial preparation in artificial cycle (AC) for embryo transfer. This is a non-inferiority, retrospective case-control study, with at least 200 cycles analyzed (at least 100 per arm) and the primary outcome is the serum progesterone level on the day of the embryo transfer.