OBJECTIVETo test whether intracytoplasmic injection of morphologically selected spermatozoa (IMSI) from patients with male factor infertility can improve the clinical and embryo development outcomes of intracytoplasmic sperm injection-embryo transfer (ICSI-ET).

METHODSWe performed IMSI for 82 couples diagnosed with obstructive azoospermia at high magnification (×6600) and traditional ICSI for another 91 couples using testicular sperms. We also performed IMSI for 44 couples with teratozoospermia at high magnification (×6600) and traditional ICSI for 71 patients using ejaculated sperms. The clinical and embryo development outcomes were compared between the cycles.

RESULTSFor obstructive azoospermia, IMSI and ICSI showed no significant difference in the rates of cleavage (95.5% vs 96.7%), D3 top quality embryos (28.2% vs 29.2%), implantation (26.4% vs 32.3%), pregnancy (47.3% vs 50%), blastocyst formation (54.3% vs 54.6%), or abortion (14% vs 7.3%) (P>0.05), but a significantly higher normal fertilization rate was achieved in IMSI group (84.3% vs 77%, P<0.05). For teratozoospermia, the 2 techniques resulted in no significant differences in the rates of cleavage (96.2% vs 95.2%), D3 top quality embryo (27.6% vs 27.1%), implantation (28.2% vs 30.7%), pregnancy (43.7% vs 43.2%), or abortion (9.7% vs 10.5%) (P>0.05), but the normal fertilization rate (68% vs 75.5%) and the blastocyst formation rate (54.6% vs 67.9% ) were significantly higher in IMSI group (P<0.05).

CONCLUSIONIMSI can improve the normal fertilization rates in couples with male factor infertility (including obstructive azoospermia and teratozoospermia) and increase blastocyst formation rate in cases of azoospermia.