Impact of a second insemination on the results of an in vitro fertilization-embryo transfer (IVF-ET) program.

In an attempt to increase the fertilization and pregnancy rates in our program, a second insemination was carried out when the first insemination yielded fewer than two fertilized oocytes. One hundred eighty consecutive patients were studied retrospectively and thirty-four required second insemination, 35% of them by donor semen. Fifty-five and nine-tenths percent of the patients had at least one fertilized oocyte for embryo transfer, but only 21.9% of the oocytes exposed to a second insemination were fertilized. No pregnancy resulted from the transfer of oocytes fertilized by the second insemination. There were no significant correlations between the success of fertilization after a second insemination and the number of oocytes retrieved, the protocol for the induction of superovulation, or the age of the female patient. Considering that the first insemination was done at a variable time after oocyte retrieval to allow oocyte maturation, we expected all oocytes to be mature at the time of first insemination and we considered the possibility of delayed fertilization as negligible since second insemination was done at least 24-30 hr after oocyte retrieval. Even though a second insemination provides further hope for the patient, by yielding additional fertilized oocytes for embryo transfer, its main value is that it may provide additional information about male fertility.