Oocyte-triggering day progesterone levels and endometrial appearance in normoresponders undergoing IVF/ICSI cycles: a hypothesis and a study protocol

In this report, we propose a study protocol capable of improving IVF outcomes in subfertile women with expected normal ovarian response. This proposal derives from conflicting published data and observations in our daily practice, concerning the negative impact of progesterone (P4) elevation at the day of oocyte triggering on pregnancy outcomes. Our hypothesis points to the combination of two previous "suspects" of reduced success after assisted reproduction techniques (ART) - the endometrium ultrasonographic parameters and P4 elevation at the day of oocyte triggering on their impact on pregnancy outcomes. Up-to-the minute data show that, there is a different impact of elevated P4 in fresh, frozen and donor cycles, whereas there are plenty of reports pointing to a different endometrial gene expression on different P4 measurements. Gaps in the literature are linked with a variation of the measurements of P4, its cycle-to-cycle reproducibility, the different cut-off levels used, the impact of various protocols of ovarian stimulation and the limitations of systematic reviews originating from the initial studies. Our hypothesis states that the combination of P4 values and endometrial ultrasound parameters at the day of oocyte triggering can affect clinical pregnancy rates in normal responders undergoing ART.