Pregnancy and Birth After Transfer of Embryos That Developed from Single-nucleated Zygotes Obtained by Injection of Round Spermatids into Oocytes

Objective: To use injection of spermatids into oocytes as a mode of infertility treatment in cases in which spermatozoa are not available.

Design: Prospective clinical evaluation and case report.

Setting: In Vitro Fertilization Unit, Herzliya Medical Centers, Herzliya-on-Sea, Israel.

Patient(s): Thirteen couples with male factor infertility in which the male partner lacked spermatozoa in the ejaculate or testicular biopsy samples.

Intervention(s): Round spermatid injection and elongated spermatid injection into oocytes.

Main Outcome Measure(s): Evaluation of the rate of two-pronucleated and single-nucleated zygote development.

Result(s): The rate of two-pronucleated zygote development after round spermatid injection and elongated spermatid injection was relatively low (27% and 36%, respectively). Single-nucleated zygotes develop more frequently after round spermatid injection and elongated spermatid injection (35% and 17%, respectively) than after intracytoplasmic sperm injection with mature spermatozoa. A normal pregnancy and childbirth resulted from the transfer of 4 cleaving embryos, each of which developed from a single-nucleated zygote in a round spermatid injection treatment cycle with ejaculated spermatids.

Conclusion(s): Embryos derived from single-nucleated zygotes after spermatid conception can be viable and give rise to an ongoing clinical pregnancy and childbirth.