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In Vitro Fertilization success (ongoing pregnancy) rates have steadily increased since the initial birth of Louise Brown. Improved understanding of stimulation protocols that optimally mature multiple oocytes safely, advances in cell culture technology and embryology lab procedures, and an enhanced ability to select couples ideally suited for success with this set of procedures have all contributed to the rise in (pregnancy) success with IVF.
The initial successful pregnancy with GIFT (Gamete Intrafallopian Transfer) was described by R. Asch in 1984. GIFT involves the laparoscopic placement of gametes (often 4 mature eggs and 50,000 sperm) within a small volume of media into the fallopian tubes. Fertilization and early embryonic development takes place in the (natural environment of the) fallopian tubes. The laparoscopic procedure is a same day surgical procedure that requires general anesthesia (patient is asleep).
During the early development of these techniques (ARTs), IVF success rates were not as high as those of GIFT. The embryology cell culture technology has rapidly developed and IVF success rates at top IVF centers now approaches and even surpasses GIFT success rates. Therefore, at the best IVF centers the more cumbersome GIFT procedure became (predominantly) obsolete since it did not confer any real advantage and it had significant additional risk (since it requires a laparoscopy).
The USA national registry (of the Society of Assisted Reproductive Technology) comparing pregnancy success rates with IVF and GIFT through 1995 shows a large increase (nearly double) in (pregnancy) success rate comparing GIFT to IVF in the earlier years (in 1988 GIFT had a 21% and IVF had a 12% delivery rate per case) and a subsequent decrease in this difference in success between these procedures (in 1995 GIFT had a 27% and IVF had a 23% delivery rate per case). In Assisted Reproductive Technology (ART) centers with lower IVF success rates, GIFT may still be an attractive option. In IVF centers with very high success rates with IVF (in the range of 50-75% per cycle in 2001), there does not appear to be any real advantage to GIFT.
Older reproductive age women (over 40 years old) may be a group that selectively benefits from GIFT over IVF. The decrease in “resilience” of these older eggs may significantly contribute to the dramatic age related decrease in IVF success. IVF certainly places the eggs and sperm in an artificial (nonphysiologic) environment for a few days (from retrieval to transfer) and this “stress” on the eggs may not be handled as well by older eggs. GIFT replaces the gametes into the fallopian tube(s) immediately following egg retrieval so that fertilization and early embryo development occurs in a far more physiologic (natural) environment. There have been reports suggesting an improved (pregnancy) success from the GIFT procedure compared to the IVF procedure for older women.
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