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GIFT, ZIFT & TET
Gamete Intrafallopian Transfer (GIFT)
This is a type of ART in which eggs and sperm are placed into the fallopian tube. The same method of ovulation induction is used as for IVF, and the egg retrieval is performed in the same manner as for IVF. Once the eggs have been retrieved they are placed, unfertilized, along with sperm into the fallopian tube by laparoscopy. This treatment requires a surgical procedure and is performed in an operating room. GIFT can only be performed if the fallopian tubes are open and normal. It is usually not as successful as IVF.
Zygote Intrafallopian Transfer (ZIFT)/Tubal Embryo Transfer (TET)
ZIFT, a combination of IVF and GIFT, transfers fertilized eggs (zygotes) into the fallopian tube. The ovulation induction process, egg retrieval, and insemination in the laboratory are performed in the same fashion as an IVF cycle. However, the zygotes are transferred into the fallopian tube the day after egg retrieval.
In TET, more mature pre-embryos are placed in the fallopian tubes on day 2 or 3 after fertilization. ZIFT and TET require a laparoscopic procedure, like GIFT. These procedures are now only rarely used. We will sometimes recommend ZIFT or TET when there is a severe cervical obstruction. ZIFT and TET, like GIFT, can only be performed if fallopian tubes are normal.
IVF Versus GIFT/ZIFT/TET
If tubal disease is a factor then only IVF can be performed and GIFT, ZIFT, or TET are not an option. Because the fallopian tube is the natural site of fertilization and early embryo development, the tubal procedures are theoretically advantageous. However, many well-controlled studies have shown no advantage in using GIFT, ZIFT, or TET over IVF. The experience of many ART programs around the world now support the contention that IVF is the procedure of choice if the embryology laboratory is of the highest quality.
Many programs have good GIFT, ZIFT, or TET success rates, but due to subtle laboratory factors, are less successful with IVF. Another major difference between GIFT and IVF, ZIFT, or TET is that with GIFT there is no documentation of fertilization. This procedure should therefore not be performed if a significant egg or sperm problem exists, or if there is any possibility that the fallopian tubes are not perfect.
A major benefit of IVF to the patient is the avoidance of a laparoscopy and the general anesthesia required for GIFT, ZIFT, and TET. We feel that the quality of our laboratory and the success of our IVF program allow us to avoid these unnecessary surgeries for our patients. The ability to transfer fewer embryos with a greater potential for implantation should make GIFT, ZIFT, and TET less appealing. GIFT procedures CAN, however, be performed if indicated or desired by the patient.