Use of metaphase I oocytes matured in vitro is associated with embryo multinucleation

Abstract

To evaluate the impact of oocyte maturational stage at retrieval on embryo multinucleation. Retrospective study. Private institution for assisted reproduction. A total of 412 patients undergoing 500 intracytoplasmic sperm injection (ICSI) cycles between August 2006 and September 2010. Routine ICSI laboratory procedures. Normal and abnormal fertilization; embryo development; arrest at pronuclear stage; failure to undergo first mitotic division; presence of embryo multinucleation; embryo quality; pregnancy, implantation, and miscarriage rates. A significantly lower percentage of multinucleation was found in embryos originating from metaphase II (MII) oocytes when compared with MI-II- and MI-derived oocytes. Significantly fewer multinucleated cells per embryo were observed in MII-derived oocytes. Clinical pregnancy and implantation rates were significantly higher when only embryos derived from MII oocytes were transferred. Embryo multinucleation rate increases when in vitro-matured (2-5 hours incubation) MI (MI-II) oocytes are used instead of in vivo-matured oocytes in ICSI. Furthermore, all other ICSI outcome parameters are also compromised. The use of donated gametes does not modify these results.