GIFT, ZIFT and TET
Fertilization and cell division naturally occur in the fallopian tube. However, for some women, infertility may be caused by conditions that prevent naturally occurring fertilization in a fallopian tube.
With both GIFT and ZIFT, like IVF, eggs are harvested from the woman’s ovaries after the woman’s ovaries are stimulated with medications to increase the likelihood of producing multiple eggs. Eggs are then are collected through an aspiration procedure.
Gamete intrafallopian tube transfer (GIFT)
Gamete intrafallopian tube transfer (GIFT) is an assisted reproductive procedure which involves removing a woman’s eggs, mixing them with sperm and immediately injecting them into the fallopian tube via a surgical procedure called laparoscopy.
One of the main differences between this procedure and IVF and ZIFT procedures is that the fertilization process takes place inside the fallopian tubes, rather than inside the laboratory. GIFT can be performed only if the patient has normal fallopian tubes and adequate sperm. For cases with abnormal fallopian tubes, IVF would be the alternative.
GIFT is the only ART approach that is completely acceptable to the Roman Catholic Church because it does not involve embryo culture and fertilization outside the body.
Zygote intrafallopian tube transfer (ZIFT)
Zygote intrafallopian tube transfer (ZIFT) is an assisted reproductive procedure similar to IVF in that the eggs are fertilized in a laboratory.
ZIFT differs from IVF in that the embryos are transferred into the fallopian tube instead of the uterus. Embryos are transferred at the zygote stage prior to cell division.
The embyros are transferred directly into the tubes through a laparoscopic procedure in which a catheter is placed deep in the fallopian tube and the fertilized eggs are injected.
ZIFT differs from GIFT in that with ZIFT, embryos are transferred to the fallopian tube rather than eggs and sperm being transferred with GIFT.
Tubal Embryo Transfer (TET)
With TET, embryos are transferred to the fallopian tube about 2 days after fertilization when the embryo has developed into 2 - 6 cells. TET is used to choose the ideal embryos for transfer after monitoring their development.
For either of these procedures to work, the woman must have at least one working fallopian tube.
Some of the reasons for choosing GIFT or ZIFT include:
- An anatomic problem with the uterus (e.g., severe intrauterine adhesions)
- Infertile couples with religious or ethical objections to laboratory fertilization may opt for GIFT because with this process, fertilization begins inside the woman’s body.
- Inability to conceive using regular IVF
- Failure of couples to conceive after at least one year of trying and who have failed 5 - 6 cycles of ovarian stimulation with intrauterine insemination.
GIFT and ZIFT v. IVF
GIFT and ZIFT are used less frequently today because traditional IVF techniques have become far more effective and IVF success rates have improved dramatically. IVF is also preferred because it is a much less invasive procedure that GIFT and ZIFT.
- An increased
chances of twins, triplets, and more, because several zygotes or gametes are
placed in the fallopian tube to increase pregnancy odds.
- Embryo quality cannot be evaluated before implantation, unlike with IVF
procedures, unless TET is used.