Zygote Intrafallopian Transfer (ZIFT)

One type of treatment for male infertility and some forms of female infertility is zygote intrafallopian transfer (ZIFT). This procedure has a fairly high pregnancy success rate of between 25 percent and 40 percent. It's suitable for treatment of a variety of infertility problems.

What Is It?

ZIFT is an assisted reproductive procedure that is comparable to in vitro fertilization and embryo transfer. The significant different between the mentioned procedures and ZIFT is that the fertilized egg is transferred into the fallopian tubes instead of directly into the uterus. Occasionally ZIFT is also referred to as tubal embryo transfer (TET). It has a higher success rate than gamete intrafallopian transfer (GIFT) because the egg is already fertilized when it is put back into the woman's body. With GIFT the egg is mixed with washed sperm and then placed in the fallopian tubes in the hope that fertilization and implantation will occur.

The Procedure

ZIFT, like many assisted reproductive procedures, requires the woman to take medication to stimulate her ovaries to produce more eggs than she would otherwise naturally produce in a cycle. Usually a woman will produce a single egg, sometimes two, during a cycle. It's necessary to harvest more than one egg for ZIFT to be successful.

Mature eggs are then removed through an aspiration procedure. For an egg to be considered mature, it must measure about 15 to 20 millimeters in diameter. The aspiration procedure involves providing the woman with anesthesia or conscious sedation so the woman doesn't feel pain. Depending on the type of anesthesia used, she won't remember the procedure either. The doctor uses an ultrasound to guide a needle through the vagina to reach the ovary and follicles. The fluid in the follicles is aspirated and the eggs detach from the follicle. They are then sucked out of the woman's body. The aspiration procedure takes approximately 10 minutes.

The eggs are then fertilized in a controlled laboratory setting using the partner's sperm or donor sperm. If there are few sperm, a single sperm will be injected into the egg to fertilize it. Other times thousands of healthy sperm will be mixed with a single egg and fertilization will occur somewhat naturally.

The fertilized eggs will be transferred deep in the woman's fallopian tubes using a minor surgical procedure called a laparoscopic procedure. This procedure involves cutting a small hole in the abdomen, then the abdominal cavity is filled with carbon dioxide, and finally a catheter is used to inject one or more fertilized eggs into the fallopian tubes.

Who Can Get This Procedure Done?

A woman needs to be ovulating (unless she chooses an egg donor) and she must have healthy fallopian tubes. Any significant tubal damage or blockage will prevent the fertilized egg from traveling to the uterus for implantation.

It's also important that the woman has no anatomic problem with her uterus or severe intrauterine adhesions, like the ones caused by severe endometriosis. These issues will prevent implantation. The male partner's sperm also needs to be healthy enough to be able to penetrate the egg.