The in vitro fertilization of supernumerary oocytes in a gamete intrafallopian transfer program.

Gamete intrafallopian transfer (GIFT) was performed on a series of 42 couples in whom four oocytes were replaced into the fallopian tubes and the remaining oocytes were inseminated with 100,000 motile spermatozoa. Fertilization in vitro was assessed 16 to 20 hours later. An overall pregnancy rate after GIFT of 40.0% (12/30) in normospermic couples and 16.7% (2/12) in oligospermic couples was seen. Supernumerary oocytes were submitted to in vitro fertilization (IVF) and the findings related to the likelihood of pregnancy. No correlation between IVF and the likelihood of GIFT pregnancies was found in either the oligospermic or normospermic couples. A similar proportion of pregnancies was seen in couples with or without evidence of fertilization of the supernumerary oocytes in both the oligospermic and normospermic couples. However, a high proportion of normospermic couples with no evidence of fertilization had only one oocyte remaining for insemination. These results suggest that the failure of low numbers of supernumerary oocytes to fertilize in vitro after GIFT relates to oocyte selection criteria and does not mean a reduced chance of conception in that treatment cycle.