11 Jan Zygote Intrafallopian Transfer (ZIFT)
Zygote Intrafallopian Transfer (ZIFT) is an assisted reproductive technology (ART) to help couples who are infertile conceive a child. It is a hybrid technique that combines in vitro fertilization (IVF) and gamete intrafallopian transfer (GIFT) procedures. It has a high success rate comparable to that of IVF, but it a more expensive and more invasive technique. Having said that, it may be better accepted and felt to be more natural because the fertilized oocyte (zygote) is placed in the woman’s body for implantation much sooner than is the case with IVF.
In order to be able to undergo ZIFT, the woman must have one healthy fallopian tube where the zygote can be implanted. The entire process takes approximately four weeks. This includes the superovulation period when she must undergo preliminary hormone treatment. During this preliminary period, she is given Clomiphene citrate (Clomid) to stimulate the ovaries to produce several mature eggs. Clomid works by increasing the levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) required for oocyte maturation. If Clomid is not enough, additional FSH and LH can be administered intravenously as well.
Once hormonally-stimulated ova are mature, they are extracted through a procedure called transvaginal oocyte retrieval, using ultrasound guidance. On the other hand, sperm is collected from the partner/donor, which is then allowed to fertilize the oocyte in a petri dish either naturally or through intracytoplasmic sperm injection (ICSI). If there is a low sperm count, a high concentration of misshapen sperm, or low sperm motility, ICSI is a good procedure to use in conjunction with ZIFT. ICSI allows the sperm to be injected directly into the egg in the petri dish to increase the chances of fertilization. While there is some concern, it is unclear whether ICSI actually increases the chances of birth defects in newborns.
After fertilization has taken place in vitro, the fertilized eggs for approximately twenty-four hours until cell starts to divide. Then, the embryo is implanted into the fallopian tube laparoscopically. The location of the implant depends on the stage of the embryo’s development. ZIFT differs from IVF as the latter uses the transcervical approach for zygote implantation. The zygote that is implanted into the fallopian tube by the ZIFT method then travels down the fallopian tube and is expected to implant on the uterine wall. In a healthy young woman, there is about 30% chance that the fertilized egg will implant do so and result in pregnancy. Multiple zygotes are placed in the fallopian tube to improve the chances of pregnancy. The greater the woman’s age, higher the number of zygotes to increase the chances of success.
There is a higher risk of ectopic pregnancy when using ZIFT. With ZIFT, the probability of pregnancy is similar to that of IVF; however, the invasiveness of the laparoscopic approach makes it a more expensive and less desirable option by comparison.