Placental abnormalities are associated with type of embryo transfer in assisted reproductive technologies (ART)

ART is associated with abnormalities in DNA methylation and a higher incidence of adverse pregnancy outcomes in humans and mice. However, which specific exposure, among the interventions utilized during ART, is responsible for these outcomes remains unknown. Embryo transfer after vitrification-thaw (frozen ET) into a maternal hormonal environment more closely resembling unassisted conception is increasingly utilized clinically, but reports suggest a higher incidence of large for gestational age (LGA) infants, with male infants potentially more affected than female infants. A prospective cohort study including patients from 2010-2020 was performed and human placentas from singleton pregnancies were obtained after: fresh IVF cycles and programmed frozen embryo transfer cycles