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

Abstract

Objective: To evaluate the impact of oocyte maturational stage at retrieval on embryo multinucleation.

Design: Retrospective study.

Setting: Private institution for assisted reproduction.

Patient(s): A total of 412 patients undergoing 500 intracytoplasmic sperm injection (ICSI) cycles between August 2006 and September 2010.

Intervention(s): Routine ICSI laboratory procedures.

Main outcome measure(s): 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.

Result(s): 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.

Conclusion(s): 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.