Gamete Intrafallopian Transfer (GIFT) is a form of Assisted Reproductive Technology (ART) designed to help couples achieve pregnancy. The name describes the procedure: “gamete” refers to the reproductive cells (eggs and sperm), and “intrafallopian transfer” means these cells are placed directly into the fallopian tube. GIFT was an early fertility treatment breakthrough, designed to facilitate fertilization inside the body, mimicking the natural biological process. The procedure involves collecting and transferring the eggs and sperm together into the fallopian tube, allowing conception to occur in its normal environment.
The Step-by-Step Procedure
The initial stage of Gamete Intrafallopian Transfer involves controlled ovarian stimulation, similar to other assisted reproductive methods. The woman receives fertility medications, typically injectable hormones, for 8 to 12 days to encourage the ovaries to produce multiple mature eggs. Physicians monitor the development of ovarian follicles using ultrasound examinations and blood tests to track hormone levels.
Once monitoring confirms the follicles are mature, a final injection of human chorionic gonadotropin (hCG) is administered to trigger the final maturation of the eggs. Approximately 36 hours later, the eggs are collected from the ovaries. This egg retrieval is a surgical procedure performed under general anesthesia, typically using a laparoscope inserted through a small incision near the navel.
In parallel with egg retrieval, a semen sample is collected and processed in the laboratory to select the healthiest, most motile sperm. The mature eggs and the prepared sperm (the gametes) are immediately mixed together in a catheter. Small air bubbles separate the contents of the catheter to prevent fertilization from occurring outside the body before the transfer is completed.
The final step is the transfer of the gametes directly into the fallopian tube using the laparoscope and catheter. The physician deposits the mixture of eggs and sperm into the fallopian tube, bypassing the sperm’s natural journey through the cervix and uterus. Fertilization is expected to occur naturally, or in vivo, within the fallopian tube, followed by the embryo’s movement toward the uterus for implantation.
Key Prerequisites for the Procedure
A fundamental requirement for GIFT is the presence of at least one healthy, functional fallopian tube. The tube must be patent, meaning it is open and unblocked, because this is the site where fertilization must take place. If both fallopian tubes are blocked or severely damaged, the procedure is anatomically impossible, and the patient is not eligible for GIFT.
The procedure also depends on the sperm having adequate quality and quantity, as fertilization is not assisted in a laboratory setting. A sufficient number of motile sperm must be available to successfully navigate the fallopian tube and fertilize the egg naturally. For the highest chances of success, the sperm sample should contain a minimum of 100,000 to 500,000 motile sperm for the transfer.
GIFT is most often considered for couples diagnosed with unexplained infertility, where the cause remains unknown after a medical workup. It may also be used for some cases of male factor infertility, provided the sperm quality is not severely compromised. Patients with tubal factor infertility (blocked or severely damaged tubes) are automatically excluded because the fallopian tubes are a necessary component of the process.
How Gamete Intrafallopian Transfer Differs from IVF
The primary distinction between Gamete Intrafallopian Transfer and In Vitro Fertilization (IVF) lies in the location where fertilization occurs. In GIFT, the eggs and sperm are transferred directly into the fallopian tube, allowing fertilization to occur in vivo (inside the woman’s body). This approach was developed to closely mimic the biological process of natural conception.
In contrast, IVF involves combining the egg and sperm in a laboratory dish, where fertilization takes place in vitro, or outside the body. With IVF, embryologists can directly observe the fertilization process and monitor the development of the resulting embryos for several days before selecting the most viable one for transfer. This allows for a level of quality control and insight into the earliest stages of conception that GIFT cannot provide.
Because fertilization is unconfirmed in GIFT, a major clinical implication is the inability to assess whether the eggs were successfully fertilized before they begin their journey toward the uterus. This means that GIFT cannot confirm the creation of an embryo prior to transfer, which is a significant difference from the IVF process. Furthermore, IVF allows the final transfer of the embryo directly into the uterus, which means it can be used successfully even if the patient has non-functional or absent fallopian tubes.
A related, though rarely performed, procedure is Zygote Intrafallopian Transfer (ZIFT), which represents an intermediate step between GIFT and IVF. In ZIFT, fertilization occurs in vitro like IVF, but the resulting fertilized egg, or zygote, is then transferred into the fallopian tube, similar to the location used in GIFT. However, both GIFT and ZIFT are performed much less frequently today, as advancements in IVF technology have made it a more efficient and less invasive option, typically not requiring the surgical laparoscopy needed for the fallopian tube transfer.