Premature Luteinization May Impact In Vitro Fertilization Outcomes Through Dual Action on Both Uterus and Embryos

This review aims to provide the up-to-date knowledge of potential mechanisms behind the putative impact of premature luteinization (PL) on the in vitro fertilization (IVF) cycle outcomes and to examine whether PL can affect embryo/oocyte quality.

There is growing evidence supporting the possible negative effect of PL on the oocyte/embryo quality in various ovarian response categories of IVF cycles.

It is generally accepted based on prior research that PL could affect pregnancy potential in fresh IVF cycles by impacting endometrial receptivity. PL is usually defined as serum progesterone (P) level equal or greater than 1.5 ng/ml on the day of ovulation triggering. Unfortunately, a way to prevent PL is still lacking. Embryo cryopreservation with deferred transfer in a subsequent cycle is so far the most widely practiced strategy to bypass the PL-induced harm on endometrial receptivity. However, embryo freezing carries an extra burden for both the IVF laboratory and patients and increases IVF cost. Moreover, there are recent reports showing that PL may adversely impact oocyte and embryo quality. It is thus of utmost importance to understand if PL adversely influences eggs and embryos; if this hypothesis is proven to be true, embryo freezing for a subsequent transfer may not improve outcomes and the management of PL may be reconsidered.