Replacement of frozen embryos generated from epididymal spermatozoa: the first two pregnancies.

This report describes the first two pregnancies which occurred after cryopreservation, thawing and transfer of embryos generated using epididymal spermatozoa from men with congenital absence of the vas deferens. Of the 32 embryos that were thawed, 24 survived (75%) and were replaced in seven transfer cycles resulting in two (29%) pregnancies successfully delivered. The demonstration that excess embryos obtained with the use of epididymal spermatozoa can be safely frozen/thawed, and that their survival is not different from other embryos generated by in-vitro fertilization, represents a great advantage for the reproductive performance of men with congenital absence of the vas deferens undergoing microsurgical aspiration of epididymal spermatozoa.