GIFT and ZIFT
Gamete intrafallopian transfer, or "GIFT," is often used for couples with unexplained infertility, mild male factor, immunologic infertility, endometriosis, and cervical factors. GIFT involves medications to stimulate the ovaries, followed by a laparoscopy to remove eggs from the ovaries and place sperm and eggs into the fallopian tube. For GIFT, one fallopian tube must be normal and healthy.
Some programs have more success with GIFT than with IVF. Considerable differences between program techniques, patient backgrounds, and means of comparing success rates exist. IVF and GIFT have not been appropriately compared in the same series of patients and it is not possible to say that one technique yields higher pregnancy rates than another.
GIFT is preferred by some religious groups because fertilization occurs within the woman's body as opposed to in a laboratory. An advantage of GIFT is that it is one procedure performed by laparoscopy, and there is no separate embryo transfer.
A disadvantage of GIFT is not being able to confirm fertilization unless pregnancy occurs. Also, a laparoscopy is necessary which is more involved than an ultrasound-guided egg retrieval.
A pre-operative visit, and orientation visit are required before starting a GIFT cycle.
Zygote intrafallopian transfer, or "ZIFT," combines the techniques of in vitro fertilization (IVF) and gamete intrafallopian transfer (GIFT) and is best used in situations where it is unclear whether or not fertilization can occur, such as with male factor infertility.
During IVF, fertilization is confirmed in the laboratory. During GIFT, fertilization is confirmed only if pregnancy occurs. During ZIFT, eggs are retrieved under ultrasound guidance as they are in IVF and GIFT. The eggs are then fertilized in the laboratory, and after confirming that fertilization has occurred, the embryos are placed into the fallopian tube by laparoscopy, within 24 hours of egg retrieval.
Some believe that ZIFT provides a higher pregnancy rate than IVF or GIFT. However, these reports are not conclusive, and not all centers have experienced better results with ZIFT.
For the ZIFT procedure, fertilization takes place in the lab after egg retrieval and other preparation has taken place. One day after egg retrieval, the fertilized egg is transferred into a normal, healthy fallopian tube by laparoscopy. The number of embryos to transfer varies. Usually four or five embryos are transferred.