Gamete and zygote intrafallopian transfer (GIFT and ZIFT) for infertility

	Treatment Overview
	What To Expect After Treatment
	Why It Is Done
	How Well It Works
	Risks
	What To Think About
	References
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Some infertile couples are affected by conditions that prevent the sperm and egg from traveling through a fallopian tube, where fertilization and the first stage of cell division take place. The following are assisted reproductive technology (ART) procedures that are rarely used but may improve the chances of conception in the fallopian tubes. The first step of each of these treatment cycles is superovulation, the stimulation of multiple egg production with a series of hormone injections.

Gamete intrafallopian transfer (GIFT) uses multiple eggs collected from the ovaries, which are placed into a thin flexible tube (catheter) along with the sperm to be used. The gametes (both eggs and sperm) are then injected into the fallopian tubes using a surgical procedure called laparoscopy under general anesthesia.

Zygote intrafallopian transfer (ZIFT) combines in vitro fertilization (IVF) and GIFT. Eggs are stimulated and collected using IVF methods, then mixed with sperm in the laboratory. Fertilized eggs (zygotes) are then laparoscopically returned to the fallopian tubes where they will be carried into the uterus. The goal is for the zygote to implant in the uterus and develop into a fetus.

Pronuclear stage tubal transfer (PROST), similar to ZIFT, uses in vitro fertilization but transfers the fertilized egg to the fallopian tube before cell division occurs.

Because of the higher costs and risks related to laparoscopy, and the lesser amount of diagnostic information about embryo development compared with IVF, these procedures are rarely used.

See a picture of the female reproductive system.

The treatment process

• Ovulation and egg retrieval. To prepare for an assisted reproductive procedure using your own eggs, you must get daily injections and be closely monitored for 2 weeks before egg retrieval. At home, you or your partner injects you with gonadotropin or follicle-stimulating hormone (FSH) to stimulate your ovaries to produce multiple eggs (superovulation). After the first week, your doctor checks your blood estrogen levels and uses ultrasound to see whether eggs are maturing in the follicles. During the second week, your dosage may change based on blood tests and other test results. If follicles fully develop, you are given a human chorionic gonadotropin (hCG) injection to stimulate the follicles to mature. The mature eggs are collected 34 to 35 hours later by laparoscopy or needle aspiration guided by ultrasound through the abdomen to the ovaries.
• Sperm collection. Sperm are collected by means of masturbation or by taking sperm from the testicle (when there is a blockage that prevents sperm from being ejaculated or when there is a problem with sperm development).
  • For GIFT, the sperm are then placed in a tube (catheter) with the eggs. The catheter is inserted through a small abdominal incision and into a fallopian tube. The eggs and sperm are then injected into the fallopian tube. Usually, two eggs are placed in each fallopian tube.
  • For ZIFT, in vitro fertilization is performed. The resulting fertilized eggs (zygotes) are injected into the fallopian tubes in the same way that GIFT is done. The zygotes then travel into the uterus, where it is hoped that they will implant and develop.

Overall, assisted reproductive technology (ART)-related injections, monitoring, and procedures are emotionally and physically demanding of the female partner. Superovulation with hormones requires regular blood tests, daily injections (some of which are quite painful), and frequent monitoring by your doctor.

You can expect to return to daily activities after a routine laparoscopic procedure in less than a week.

GIFT may be appropriate when:

• A couple has religious objections to fertilization taking place outside the body.
• A couple with unexplained infertility only has insurance benefits for GIFT.

For GIFT or ZIFT, a woman must have at least one functional fallopian tube.

The latest national success rates for assisted reproductive technologies are available through the Centers for Disease Control and Prevention (CDC). See the complete CDC listing of U.S. infertility clinics online in the latest Assisted Reproductive Technology Success Rates report at http://www.cdc.gov/reproductivehealth/art.htm.

Risks resulting from laparoscopy (which may be used to collect eggs) include pelvic infection, puncture of internal organs, and side effects from general anesthesia.

Assisted reproductive technologies—including GIFT and ZIFT—increase the risk of multiple births.¹ A multiple pregnancy is high-risk for both the mother and the fetuses.

ZIFT success versus the risk of multiple pregnancy

In order for a woman over age 35 to maximize her chances of conceiving with her own eggs and carrying a healthy pregnancy, she must have more embryos transferred than a younger woman would. This increases her risk of multiple pregnancy.

Because of the risks to the babies of multiple pregnancy, the American Society for Reproductive Medicine (ASRM) recommends that women under age 35 have no more than two embryos transferred, women age 35 to 37 have no more than three, women 38 to 40 have no more than four transferred, and women who have had repeated failed cycles or are over age 40 have no more than five embryos transferred in a ZIFT procedure. Since all the eggs transferred in GIFT may not become fertilized, the ASRM recommends one more egg be transferred in each of these age categories. For example, a woman under age 35 could have up to 3 eggs transferred.²

Women over 40 have a high rate of embryo loss when using their own eggs. As an alternative, older women can choose to use more viable donor eggs.

ZIFT and GIFT procedures using gametes from both partners account for less than 2% of all ART procedures. The majority of couples in the United States use in vitro fertilization.³

ART birth rates can be misleading. As a woman ages past her mid-30s, her egg quality and quantity decline, making it increasingly unlikely that an ART procedure using her own eggs will result in pregnancy and a healthy baby. Many women over age 40 choose to use donor eggs, which greatly improves their chances of giving birth to a healthy child.

ZIFT requires two separate procedures. The first procedure is to collect the eggs from the woman's ovaries. The second procedure is done several days later when the fertilized egg (zygote) is placed in her fallopian tube.

If GIFT fails, a doctor does not learn anything about the sperm's ability to fertilize the eggs. With in vitro fertilization, the sperm fertilizes the egg in the laboratory, where a health professional can tell whether fertilization has occurred, and can follow embryo development.

ZIFT and GIFT procedures both cost approximately $15,000 to $20,000 per attempt. In vitro fertilization usually costs less.

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Citations

1. Centers for Disease Control and Prevention (2006). Assisted Reproductive Technology (ART) Report: 2005 Preliminary Clinic Data by State and National Summary. Available online: http://apps.nccd.cdc.gov/ART2005/clinics05.asp.

2. American Society for Reproductive Medicine (2006). Guidelines on number of embryos transferred. Fertility and Sterility, 86(4): S51–S52.

3. Speroff L, Fritz MA (2005). Assisted reproductive technologies. In Clinical Gynecologic Endocrinology and Infertility, 7th ed., pp. 1216–1274. Philadelphia: Lippincott Williams and Wilkins.