Birth after the injection of sperm and the cytoplasm of tripronucleate zygotes into metaphase ii oocytes in patients with repeated implantation failure after assisted fertilization procedures

Objective: To assess the technique of injecting a single sperm and cytoplasm obtained from tripronucleate zygotes into metaphase II oocytes for the treatment of patients with repeated implantation failure after intracytoplasmic sperm injection or IVF. Design: Clinical study. Setting: Private infertility clinic. Patient(s): Patients with repeated implantation failure after intracytoplasmic sperm injection or IVF. Intervention(s): The metaphase II oocytes of recipients were injected with their husbands' spermatozoa and cytoplasm aspirated from the tripronucleate zygotes of donors. Main Outcome Measure(s): Fertilization after cytoplasm and sperm injection, embryo development, and successful pregnancy. Result(s): In total, 62 metaphase II oocytes from nine recipients were injected. Of the 62 injected oocytes, 3 (5%) degenerated and 43 (69%) had two pronuclei 18 hours after injection. Thirty-nine oocytes with two pronuclei cleaved to the two-cell to six-cell stage after another 24 hours of culture. All cleaved embryos were transferred into the uteruses of recipients. Four clinical pregnancies occurred in four recipients. No abnormal chromosomes were observed after amniocentesis and karyotyping in all pregnancies. Five healthy infants were born. Conclusion(s): Injection of the cytoplasm of tripronucleate zygotes may enhance the clinical pregnancy rate in patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.