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GIFT and ZIFT
Some infertility may be caused by conditions that prevent fertilization in a fallopian tube, where fertilization and cell division naturally occur. GIFT (gamete intrafallopian transfer) and ZIFT (zygote intrafallopian transfer) procedures may help. They’re similar in that both harvest eggs from a woman’s ovaries and re-implant them, but the difference lies in how they’re placed. With GIFT, the gametes - individual eggs and sperm - are placed into the woman’s fallopian tubes. With ZIFT, fertilized eggs called zygotes, are placed in the women’s fallopian tubes after they’ve been fertilized in a lab via in vitro fertilization (IVF). In traditional IVF, fertilized eggs are implanted in a woman’s uterus after they grow for 3 to 5 days in the lab. In ZIFT, several fertilized eggs are surgically placed in a woman’s fallopian tube(s) within 24 hours of fertilization.
In both ZIFT and GIFT, the woman is first injected with hormones to stimulate production of multiple eggs (versus one egg as in a natural cycle). In GIFT, the sperm (either the woman’s partner’s or a donor’s) and the woman’s harvested eggs are simply placed together in the fallopian tube; in ZIFT, several fertilized eggs are placed in the fallopian tube(s). If all goes well, in both processes, the fertilized eggs travel down the fallopian tube(s) and implant in the woman’s uterus, and the fetus develops. Both require a procedure to extract the eggs (surgically with laparoscopy, or using transvaginal guided ultrasound) as well as laparoscopy to then insert the fertilized eggs or gametes (sperm and eggs) in the fallopian tubes.
Who's Treated With It?
The main candidates for GIFT and ZIFT are women with at least one working fallopian tube who haven't been able to conceive using regular IVF. Infertile couples with religious or ethical objections to laboratory fertilization may opt for GIFT because in this process, fertilization begins inside the woman’s body.
GIFT and ZIFT are used less frequently today because traditional IVF techniques have become far more effective. A downside to both is increased chances of twins, triplets, and more, because several zygotes or gametes are placed in the fallopian tube(s) to increase pregnancy odds. Multiple births are associated with premature and low-weight newborns, higher rates of caesareans, and infant disabilities and even prenatal death. Another negative of both is that the embryo quality cannot be evaluated before implantation, unlike with IVF procedures.
Success rates, measured by live births, depend on the embryo’s quality, the woman’s age, and the number of embryos transferred.