Use of zona pellucida-bound sperm for intracytoplasmic sperm injection produces higher embryo quality and implantation than conventional intracytoplasmic sperm injection.

This goal of this study was to compare the outcomes of conventional intracytoplasmic sperm injection (ICSI; control group, n = 53 couples) and a modified ICSI technique using zona pellucida (ZP)-bound sperm for injection of oocytes (test group, n = 53 couples). The proportion of high-quality embryos (grades 1 and 2) and implantation rate were significantly higher in the test group than in the control group, but the difference in fetal heart pregnancy rate was not significant despite seven more pregnancies being obtained in the test group (26 pregnancies) versus the control group (19 pregnancies) following fresh embryo transfers.