High fertilization and pregnancy rates after intracytoplasmic sperm injection in patients with disordered zona pellucida-induced acrosome reaction.

Objective: To determine whether intracytoplasmic sperm injection (ICSI) is effective treatment for patients with disordered zona pellucida (ZP)-induced acrosome reaction (AR) who have failure of standard IVF-ET.
Design: Tests of sperm-ZP binding and penetration and the ZP-induced AR were used to diagnose patients with disordered ZP-induced AR who then were treated with ICSI.
Setting: Academic reproductive medicine research laboratory associated with a tertiary referral infertility clinic.
Main Outcome Measure(s): Clinical features and results of previous IVF-ET, semen analysis and sperm-ZP interaction tests, and ICSI were analyzed.
Result(s): The majority of patients had consistently normal sperm characteristics and all patients had normal sperm-ZP binding but failure of sperm-ZP penetration. The AR of sperm bound to the ZP was significantly lower in the patients (mean 6%, range 0% to 16%) than in the fertile men (mean 61%, range 27% to 96%). Intracytoplasmic sperm injection was performed on 34 patients and the normal fertilization rate averaged 73% per injected oocyte. Five ongoing and eight term pregnancies including two with twins were achieved after an average of two ET procedures per patient were performed. Two couples have second ongoing pregnancies from transfer of frozen embryos after successful first pregnancies. Overall, the implantation rate was 10.5% per embryo and the pregnancy rate 19% per ET and 38% per patient.
Conclusion(s): Disordered ZP-induced AR is a cause of severe infertility and persistent failure of IVF-ET. Intracytoplasmic sperm injection is effective treatment for this condition. Patients with idiopathic infertility should be tested for this condition before commencing IVF-ET treatment.