ZIFT/TET is another variant of the IVF procedure and was developed in about 1986. As with IVF and GIFT, ZIFT involves ovarian stimulation monitoring and egg retrieval. The major difference between ZIFT and GIFT is that once the eggs are retrieved, they are fertilized in the in vitro laboratory, just as they are in the IVF procedure. The difference between IVF and ZIFT is that the zygotes, or embryos, are then transferred laparoscopically to the fallopian tubes in a manner similar to a GIFT transfer.

The obvious advantage of ZIFT over GIFT is that, as in IVF, it is possible to document fertilization. On the other hand, the procedure requires the woman to have at least one functioning fallopian tube, which is a disadvantage when comparing ZIFT to IVF.

The use of ZIFT is not that widespread. However, at HRC we have leaned towards performing ZIFT on a select group of patients because early on we noticed an increase in pregnancy rates especially amongst older patients and those with unexplained infertility.
HRC's overall take home baby rate for 500 egg retrievals performed for ZIFT is 48%. This elivered rate includes 81 egg retrievals performed on patients over 40 years of age.

The above data suggests that at our center patients who have had multiple failed IVF cycles or who have patent tubes but are older should consider ZIFT/TET as a treatment option. It is possible that the fallopian tube may have the capacity to rescue "marginal embryos" as well as allowing the developing embryos to remain in the tube and then as in a natural pregnancy move into the uterus at the appropriate physiological time for implantation.