Abstract: Abstract: Objective To 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). Methods We 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. Results For 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). Conclusion IMSI 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.