Birth and perinatal outcomes and complications for babies conceived following ART.

Children born after assisted reproductive techniques (ART) have an increased risk of several adverse perinatal outcomes compared with their naturally conceived peers. This has various causes such as higher multiple birth rates, parental characteristics and higher maternal age, with more being nulliparous. Furthermore the in-vitro techniques, the controlled ovarian stimulation, culture media, and possibly additional freezing or vitrification procedures seem to play a role. However, when analyzing the perinatal trends over time, the differences between ART and naturally conceived children appear to have diminished. This is probably due to ART being more accessible and therefore couples have shorter duration of infertility before referral to ART; hence couples are nowadays less reproductively ill than in the past. A refinement of both clinical and laboratory skills during the past three decades of assisted reproduction may be another explanation. However, caution should be taken, as we do not yet know the full consequences of the observed increase in fetal growth and potential epigenetic changes in the early embryonic stages of fetal development.