OBJECTIVETo evaluate the impact of sperm midpiece morphology observed under high-power microscope on embryo development following intracytoplasmic morphologically selected sperm injection.

METHODSMorphologically normal sperms from 57 patients undergoing intracytoplasmic sperm injection (ICSI) for male-factor infertility were selected microscopically (magnification of ×200 or 400) and subjected to motile sperm organellar morphology examination (MSOME) at high magnification of ×6000. According to the morphology of sperm medpiece, the sperms were divided into 3 groups, namely group A with a/b of 1-1.2, group B with a/b≥1.5, and group C with irregular morphology. The sperms in the 3 groups were intracytoplasmically injected in oocytes and the outcomes of the embryos were compared.

RESULTSGroups A, B, and C showed significant differences in the rate of ET-D3 top quality embryo (79.7% vs 55.6 % vs 33.3%) and implantation rate (43.2% vs 11.1% vs 0%), but not in the fertilization rate (73.3% vs 80.4% vs 63.5%), blastocyst formation rate (23.2% vs 22.2% vs 9.09%), cryopreservation rate (29.2% vs 25.0 % vs 13.0%), or D3 top quality embryo rate (35.3% vs 37.8% vs 18.8%).

CONCLUSIONSIn ICSI cycle, selecting morphologically normal sperms for intracytoplasic injection can increase the normal fertilization rate and top quality embryo rate on the transfer day and improve the implantation rate of the embryo.