Effect of letrozole on moderate and severe early-onset ovarian hyperstimulation syndrome in high-risk women: a prospective randomized trial

Letrozole was more effective than aspirin in decreasing the incidence of moderate and severe early-onset ovarian hyperstimulation syndrome. Our results indicate that ovarian hyperstimulation syndrome might be caused through a luteolytic effect rather than through modulation of vascular endothelial growth factor, racing by a decline in estradiol and termination of early-onset ovarian hyperstimulation syndrome in advance in high-risk women with cryopreservation of the whole embryos.