Subzonal insemination for the alleviation of infertility.

Methods were developed to facilitate the use of subzonal insemination to achieve fertilization in vitro. A clinical trial was undertaken in those patients having previously failed to achieve fertilization by in vitro fertilization, and in those presenting with severe oligospermia/oligoasthenospermia. From 85 patients, 585 oocytes were obtained. Of these, 0.3% had been "activated" parthenogenetically in vivo, 369 (72%) at metaphase II underwent subzonal insemination, 15% were fertilized, and 0.5% had three pronuclei. Thirty-eight percent of the patients had fertilization with 36% having a replacement. One conceptus was replaced in 19 patients, two conceptus in 8 patients, and three in 4 patients. A twin and two singleton pregnancies were established.