NORMAL FERTILIZATION AND EMBRYO DEVELOPMENT BY INTRACYTOPLASMIC SPERM INJECTION OF ROUND-HEADED ACROSOMELESS SPERM

Objective: To investigate the ability of round-headed acrosomeless sperm to bind to the human zona pellucida (ZP) and oolemma and to fertilize human oocytes by intracytoplasmic sperm injection. Design: Oocytes that had failed to fertilize in IVF were used for sperm-ZP and spermoolemma binding tests. Sperm from a fertile donor was used as a control for oocyte variability. Intracytoplasmic sperm injection was used for assisted fertilization. Setting: University- and hospital-based reproductive research laboratory and tertiary referral IVF program. Patients: Case study of a couple in which the man has 100% round-headed acrosomeless sperm in the ejaculate. Main Outcome Measure: Fertilization and embryo development and the ability of sperm to bind to the ZP and oolemma. Results: No ZP or oolemma binding was achieved, but normal fertilization and embryo development was obtained after intracytoplasmic injection of round-headed acrosomeless sperm. However, no pregnancy was achieved after the transfer of two cleaving embryos. Conclusions: Normal fertilization and embryo development from round-headed acrosomeless sperm is possible with intracytoplasmic sperm injection. However, it remains to be reported whether pregnancy can result from fertilization with this type of sperm defect.