Artificial donor insemination: fresh versus frozen semen; the patient as her own control.

The efficacies of fresh versus cryopreserved semen in the treatment of male factor infertility by artificial insemination by donor (AID) semen were directly compared by using the patient as her own control. In any one cycle, either fresh or frozen semen was used. The type of semen preparation was randomly assigned for the first cycle and varied thereafter according to donor availability. The same donor was used for a given patient in six consecutive cycles. We treated 381 patients in this way. In 676 cycles fresh semen was used and 128 pregnancies were achieved. Fecundability, the chance of getting pregnant per cycle of exposure, was 18.9% with fresh semen. In 1200 cycles cryopreserved semen was used and 60 pregnancies occurred, for a fecundability of 5.0%. Therefore, in our clinic, fresh semen is more than three times as likely to induce pregnancy as frozen semen. The design that has been used in this therapeutic protocol provides a technique for internal quality control of the cryopreservation process and for the investigation of other variables potentially affecting the success rates with AID.