Perinatal complications in pregnancies achieved using donor oocytes

Oocyte donation (OD) is a widely performed reproductive technique. There is agreement concerning its high pregnancy rates. However, there is some concern regarding certain perinatal conditions associated with OD pregnancies. We performed a revision of seven published meta-analyses on the topic. Across studies, they have reported an increased rate of hypertensive disorders, gestational diabetes, cesarean sections, preterm delivery, and low birth weight, among other pregnancy complications. Some of these impaired outcomes may be due to other associated conditions by themselves: advanced maternal age, multiplicity, in vitro fertilization (IVF) pregnancy, and nulliparity, as well as to underlying conditions, mainly of a cardiovascular or immune nature. It has been speculated that the embryo/fetal mismatching with the mother (much higher in OD pregnancies than in pregnancies with own oocytes) could play a role, triggering an immune reaction that could impair pregnancy outcome, since this is one of the mechanisms postulated in the development of preeclampsia. It is concluded that in women <50 years, where a thorough medical evaluation has ruled out conditions that could impair pregnancy, if single embryo transfer (SET) is performed, OD is a highly successful and safe alternative.