von Versen-Höynck F, et al. - In early pregnancy, researchers investigated whether a nonphysiological hormonal milieu, a modifiable state, affects maternal vascular health. In frozen embryo transfers [FETs] with suppressed corpus luteum (CL) compared to FETs in a natural cycle, only FET cycles, a lower reactive hyperemia index and a higher increase index were observed. In the absence of CL in FETs, the number of angiogenic and nonangiogenic endothelial progenitor cells was lower. In women with aberrant numbers of CL (0 or > 3), vascular health in early pregnancy is altered and might not be sufficient cardiovascular adaptation to increase the risk of preeclampsia.