What is the Frozen Embryo transfer (FET)

FET stands for Frozen Embryo Transfer. FET is a cycle in which a frozen embryo from a previous fresh IVF cycle is thawed and transferred back to the woman's uterus. This means that you don't have to go through another cycle of hormonal stimulation and egg collection.

The frozen embryo cycle can be carried out either in the natural cycle or by using hormone preparation or ovulation induction.

Clinical Studies of FET:

Some clinical studies have shown that hormonal interventions can be harmful to endometrial receptivity and pregnancy success. Thus, in the absence of hormonal intervention, the true effect size of the FET in the natural cycle may be higher. Importantly, more than 1,000 patients have been recruited to new multicenter randomized trials (Antarctic trials) to assess the impact of natural and artificial FET cycles on numerous outcomes such as living, health costs, adverse events, and suffering and their outcomes are eagerly anticipated.

Studies validating these positive outcomes for women who are older or poor responders and natural cycle FET are certainly necessary, but the evidence so far further solidifies the principle that better and safer pregnancy outcomes can be achieved with FET, and therefore, the burden of proof now seems to have shifted to those advocating fresh embryo transfer.

What are the Benefits of FET?

Ten years ago, Min and his colleagues strongly advocated a new indicator, BESST (Birth Emphasis on Successful Single Person in office), to measure the best outcome of the IVF cycle. The BESST results are designed to coordinate international reporting and to pay attention to the most important outcomes for patients, the delivery of healthy babies, and the burden of a couple’s treatment.

Thus, for each IVF cycle initiated, delivery of a single, long-term pregnancy, live baby is the most relevant and most important criterion for success. Under this philosophy, a "freeze all" or FET strategy can be proposed as a safer way to achieve the best results for both IVF.

Success Rates with Elective FET?

A stronger argument to support the adoption of FET as a default IVF protocol is the potential for higher pregnancy rates. A systematic review and meta-analysis of three randomized controlled trials, including 633 women, assessed clinical and ongoing CPRS and abortion rates after effect and fresh embryo transfer. The overall conclusion is that FET leads to an increase in cardiopulmonary resuscitation and a persistent pregnancy rate with no difference in abortion rates.

It is important to interpret these data with vigilance. It remains to be seen whether these findings apply to women with poorer prognostic outcomes. However, a preliminary study was conducted for women over 35 years of age, and it appears that these findings may prove to be in "poor prognosticate" populations.

In addition, it did not report the live-birth rate, although a meta-analysis found that conclusions based on the clinical efficacy of pregnancy or live births as a terminal. It will certainly be more reassuring to find that the cumulative living rate retrieved from one oocyte is equal. Finally, in the absence of health economic data, the cost implications of these two strategies (fresh or frozen transfers) remain unclear.

What is Embryo freezing/ Cryopreservation?

In most cases, cryopreservation is performed when an "extra" embryo after a regular IVF cycle. “Fresh" transfer is usually preferred. However, some doctors recommend selective frozen embryos. This transfer is also identified as an "all frozen" method. In this case, all embryos are cryopreserved and transferred in the FET cycle around the next month.

The scientific value of cryopreservation of embryos has progressively increased over the decades due to technological advances inability to freeze embryos in the cleavage stage and blastocyst stage. The first success of cryopreservation is achieved through slow freezing, which has been the preferred method for cryopreservation of embryos for the past two decades. Recently, the optimization of the verification method, the use of cryoprotectants and rapid freezing, has become more widely used. If implemented correctly, vitrified embryos after thawing have excellent survival.

A number of vitrified reports show a ninety-five percent survival rate. In addition, vitrification of embryos was assessed by clinical results shows that CPRs is Compared with slow freezing embryos, the vitrification group in the vitrification group was 50% higher, and similar results were seen in the ongoing pregnancy and implantation rates.

Australian Concept Infertility Medical Center first IVF Clinic was established in March, 1998 in Karachi. In fact, this was the first time in the IVF history of Pakistan that Consultants, Embryologists and Nursing staff were flown overseas to acquire state of the art and the most advanced hands on assisted reproductive training and quality assurance techniques. ‘ACIMC’ is proudly Pakistan’s 1st ISO 9001:2015 Certified IVF Clinic with the largest presences having clinics in all major cities of Pakistan.