Zygote intrafallopian or intrafallopian zygote transfer(ZIFT) is an assisted reproductive technique that involves the transfer of zygotes directly into the patient's fallopian tubes. The zygote is the cell resulting from the fertilization of an ovum by a spermatozoon, from which the embryo will develop.
ZIFT is rarely used, as the most common transfer method today is blastocyst-stage embryo transfer into the woman's uterus.
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What is ZIFT?
ZIFT is an assisted reproductive technique characterized by the transfer of a zygote-stage embryo into the woman's fallopian tubes. This implies that fertilization for ZIFT occurs in the laboratory, in vitro, as in other assisted reproductive techniques.
However, ZIFT is undoubtedly one of the least used assisted reproduction techniques at present, as there are other less invasive alternatives.
Assisted procreation, as any other medical treatment, requires that you rely on the professionalism of the doctors and staff of the clinic you choose. Obviously, each clinic is different. Get now your Fertility Report, which will select several clinics for you out of the pool of clinics that meet our strict quality criteria. Moreover, it will offer you a comparison between the fees and conditions each clinic offers in order for you to make a well informed choice.
How is it done?
The procedure for performing intratubal zygote transfer begins in the same way as in regular in vitro fertilization (IVF) cycles.
First, a controlled ovarian stimulation with hormonal treatment is performed. Its purpose is to obtain a greater number of oocytes, unlike what occurs in a natural cycle. When the follicles reach the right size, ovulation is triggered and follicular puncture is performed before ovulation occurs.
Follicular puncture is performed under sedation and consists in the aspiration of the oocytes by means of a needle guided by ultrasound. The oocytes obtained in this way are fertilized in the laboratory with spermatozoa from the couple or from a donor.
After approximately one day, embryologists assess how many oocytes have been successfully fertilized. From this point on, the ZIFT procedure begins to differ from a regular IVF procedure. In the case of ZIFT, the zygotes are transferred directly into the patient's fallopian tubes. In contrast, in conventional IVF, embryos would be cultured until day 3-5 of development before being transferred to the patient's uterus.
The transfer of the zygotes to the tubes in ZIFT is usually performed laparoscopically and under general anesthesia. From the tubes, the zygotes must travel the path they would naturally take to reach the uterus. Here the embryo must implant to give rise to a gestation.
Requirements for ZIFT
In order to be able to perform the ZIFT technique, the patient must not have any type of obstruction or damage to the tubes. At least one of the fallopian tubes must be patent to be eligible for ZIFT. The explanation is that the embryo has to travel through the tubes, where it has been introduced, to go to the uterus and implant.
On the other hand, it is not advisable to perform ZIFT in patients with uterine problems or a history of ectopic pregnancies.
Advantages and disadvantages
Like all assisted reproductive techniques, ZIFT has a number of advantages and disadvantages.
The main advantage of ZIFT over conventional IVF is that it is a more physiological-like procedure. ZIFT reduces the time the embryo is in the laboratory, since the embryo will be developing inside the woman's body.
On the other hand, synchronization of the embryo with endometrial development is optimal in ZIFT. In addition, intrauterine manipulation is avoided in ZIFT, so intratubal transfer was proposed as an alternative for patients with repeated implantation failures in IVF cycles and conventional embryo transfer. However, results on whether or not these patients benefit from ZIFT are conflicting.
Finally, ZIFT also has an advantage over gamete intrafallopian transfer (GIFT).
Gamete intrafallopian gamete transfer (GIFT) consists of inserting the eggs and sperm into the patient's fallopian tube so that fertilization can take place inside it. For this reason, it is not possible to check whether fertilization has occurred correctly.
ZIFT allows laboratory confirmation that fertilization has occurred correctly.
There are several points against ZIFT. On the one hand, ZIFT requires surgery, which entails greater difficulty, risk and cost. In contrast, uterine transfer only requires the introduction of the embryos through the cervix with a fine cannula and is a painless procedure.
Another disadvantage of ZIFT is that a higher percentage of ectopic pregnancies may occur, since the embryos are not transferred directly into the uterus.
It is also important to mention that, since it is normal to introduce more than one zygote, the rate of multiple pregnancies may be higher than in other types of techniques.
For all these reasons, ZIFT has been displaced by IVF followed by transcervical embryo transfer.
FAQs from users
Why is ZIFT in disuse?
Transtubal transfer is no longer used, since the highest pregnancy rate is achieved with intrauterine embryo transfer.
In the past, ZIFT was a technique that was performed, but its results are not as good as in utero transfer. Likewise, it is a more invasive technique, since it requires sedation of the patient and is performed laparoscopically.
Currently, embryos can be transferred at day 5 (blastocyst), the maximum that technology allows today.
What is the price of intratubal zygote transfer?
The cost of assisted reproductive techniques depends on the fertility clinic, so the price of ZIFT may vary.
However, not all clinics offer ZIFT because it is a more invasive method that requires surgery. Therefore, the price of ZIFT in the clinics that offer it is usually higher than that of an IVF cycle with conventional intrauterine transfer.
What are the risks of ZIFT?
ZIFT is not a risk-free technique. In addition to the risks common to other assisted reproduction techniques such as ovarian hyperstimulation syndrome (OHSS), ZIFT involves possible complications arising from laparoscopic surgery and a high rate of ectopic and multiple pregnancies.
Suggested for you
If you would like to learn more about in vitro fertilization, we recommend you read the following article: In vitro fertilization (IVF): What is it and how much does it cost?
If, on the other hand, you are interested in uterine embryo transfer, you can visit the following link: Embryo transfer: when and how is it done?
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FAQs from users: 'Why is ZIFT in disuse?', 'What is the price of intratubal zygote transfer?' and 'What are the risks of ZIFT?'.
Woww! I’ve never heard of that method before. Honestly I find it quite risky and doomed to failure. I guess that’s the reason why it is unusual and not many people undergo it… But I admit it’s rather interesting though.