Frozen embryo transfer and preeclampsia: where is the link?

The use of assisted reproduction treatments (ART) has progressively expanded in contemporary medi- cine. With the advent of vitrification, better sur- vival rates after thawing have been reported, and thus, a greater number of embryos undergo this process. Frozen embryo transfer (FET) can be per- formed in a natural cycle or in under hormonal replacement protocols. Recent studies associate perinatal outcomes in pregnant patients after ART with a higher incidence of gestational hypertensive disorders, such as preeclampsia, and severe pre- eclampsia. These results are even more evident in patients undergoing frozen embryo transfer, espe- cially when preceded by cycles of artificial endome- trial preparation. In these cycles, estrogen and progesterone are usually replaced, without the development of corpus luteum. Considering that corpus luteum secretes other substances that con- tribute to physiological circulatory adaptation in the first trimester of pregnancy, its absence could be a key player.