Fig. 1

Representative normozoospermic spermatozoa with IVF pregnancy or R-ICSI pregnancy after conventional IVF treatment. a1 The retrieved oocyte was incubated with the normal sperms, and the concentration of sperms was 300,000/mL; a2 Two polar bodies were visible at 4 h after IVF; a3 Two pronuclei were visible at 16 h after IVF, which was considered as normal fertilization; a4 day 3 cleavage stage embryo; a5 Clinical pregnancy was confirmed by ultrasonographic evidence of the fetal heartbeat at 6 weeks of gestation. b1 The retrieved oocyte was incubated with the normal sperms, and the concentration of sperms was 300,000/mL; b2 No second polar body was visible at 4 h after IVF; b3 R-ICSI was performed at 5 h after IVF; b4 Two pronuclei were visible at 16 h after IVF, which was considered as normal fertilization; b5 day 3 cleavage stage embryo; b6 Clinical pregnancy was confirmed by ultrasonographic evidence of the fetal heartbeat at 6 weeks of gestation