Pregnancies following pronuclear stage tubal transfer.

Pronuclear stage tubal transfer (PROST) is a technique that involves in vitro fertilization (IVF) of oocytes, followed by the transfer of pronuclear oocytes into the fallopian tubes. It has been developed for its prognostic value of confirming fertilization in couples with oligospermia or asthenospermia and enabling fertilization in cases with antispermatozoal antibodies (ASAB). PROST has provided useful diagnostic information in the management of couples who have failed to conceive in other treatment programs and has particular advantages over IVF for those receiving fresh donated oocytes for ovarian failure. Fourteen pregnancies resulted from 52 transfers, providing a pregnancy rate of 27% per transfer. The pregnancy rates were higher than a matched IVF series in the male factor and female ASAB groups and reached statistical significance for the ovum donation group. It is anticipated that both pregnancy rates and fetal wastage will be improved over conventional IVF and embryo transfer for the described infertility groups.