Failure of oocyte activation after intracytoplasmic sperm injection using round-headed sperm

Objective: To examine the outcome of intracytoplasmic sperm injection (ICSI) with round-headed sperm (globozoospermia). Design: Retrospective analysis. Setting: In vitro fertilization laboratory with extensive ICSI experience. Patient(s): A patient couple with infertility because of globozoospermia seeking ICSI treatment. Main Outcome Measure(s): Fertilization, cleavage, and pregnancy rates. Intervention(s): Intracytoplasmic sperm injection and calcium ionophore. Result(s): This couple experienced only 7% fertilization after ICSI in their first cycle. Treatment of the unfertilized oocytes with calcium ionophore 20 hours after ICSI-induced fertilization and cleavage of 79% of the oocytes. Embryo quality was fair to good. On the second cycle, 8 of the injected oocytes were treated with ionophore immediately after ICSI and the remaining 20 oocytes were untreated. Normal fertilization was achieved in 75% of the treated and 10% of the untreated oocytes. Treatment of these unfertilized oocytes with ionophore 20 hours after ICSI resulted in fertilization in 73%. Pregnancy was not achieved after either ICSI cycle. Ultrastructural analysis indicated multiple structural abnormalities in the sperm. Conclusion(s): These results indicate that the round-headed sperm from this patient were incapable of oocyte activation after ICSI. This may be the reason for the frequent ICSI fertilization failure seen with this condition. Current ICSI procedures may not always overcome the infertility associated with globozoospermia, and further study of the etiology of this condition is needed.