Progesterone (P4) Elevation on Day of Human Chorionic Gonadotropin (HCG) Trigger Predicts Lower Pregnancy Rate During in Vitro Fertilization (IVF) Cycles

The effect of late follicular P4 elevation on IVF success has been previously evaluated, with conflicting results. Supraphysiologic estradiol (E2) and P4 elevations may be detrimental to endometrial receptivity, resulting in premature closure of the implantation window, and a subsequent decrease in pregnancy rates. Though there is growing evidence for the negative effect of elevated P4 on day of hCG trigger, fewer studies have looked at P4 elevations leading up to day of trigger, which may more accurately reflect changes in the endometrium than a single value on day of trigger.