Epigenetic consequences of assisted reproduction and infertility on the human preimplantation embryo.

Epigenetic information, which is essential for normal mammalian development, is acquired during gametogenesis and further regulated during preimplantation development. The epigenetic consequences of assisted reproductive technologies (ARTs) and infertility on the health and quality of the human preimplantation embryo are considered in this review. In the zygote, the epigenetic information that is inherited from the sperm and the oocyte intersects and must be appropriately recognized, regulated and then propagated during preimplantation development so as to regulate gene expression in an appropriate manner. A growing body of evidence suggests that ARTs and/or infertility itself may affect these complex processes leading to epigenetic diseases that include disorders of genomic imprinting. The epigenetic safety of human gametes and embryos is of paramount importance. Unfortunately, morphological methods of assessing embryo quality are incapable of detecting epigenetic errors. Further research is therefore critical to resolve these issues.