Infertility Treatments

Frozen Embryo Transfer (FET) 

The replacement of a thawed embryo into a patient’s uterus, after being frozen during a previous fresh treatment cycle. 

What is a Frozen Embryo Transfer? 

A frozen embryo transfer is the transfer of a frozen-thawed embryo back into the patient’s uterus.  

Why are Frozen Embryo Transfers used? 

Often, after a conventional IVF or ICSI cycle, a patient will have embryos surplus to their needs at the time. Provided these embryos are of suitable quality, they can be cryopreserved (frozen) for use at a later time during a frozen embryo transfer (FET) cycle. 

What is the Frozen Embryo Transfer process? 

Generally speaking, the frozen embryo transfer process is significantly less invasive and more tolerated than conventional IVF and ICSI treatment, and uses lower doses of medication (if any).  

Step 1a: Natural FET

In a natural frozen embryo transfer cycle (where no medications are used before the embryo transfer), the cycle is tracked for ovulation, using blood tests to monitor the hormone levels.  As ovulation draws near, an ultrasound is conducted to assess the growth and development of the endometrium (the lining of the uterus).  When this is suitable, the embryo thaw and transfer will be scheduled accordingly.  

Step 1b: Stimulated FET

In a stimulated frozen embryo transfer cycle, hormone medication is administered in order to promote the growth and development of the endometrium, ready for implantation. This can be done with conventional FSH hormones or using hormone replacement therapy (HRT).  Using ultrasound, the endometrium is monitored and when it is deemed suitable, a trigger injection is given to induce endometrial receptivity.  

Step 2: Embryo thaw 

The timing of your embryo thaw will be carefully calculated to ensure that your embryo is being transferred into your uterus when it is at its most receptive.      

Step 3: Embryo Transfer (ET)

The embryo transfer procedure in an FET cycle is no different from that during a conventional IVF or ICSI cycle.  The doctor will very gently insert a speculum into your vagina, and a fine, soft tube is then carefully  passed through the cervix allowing the embryo to be placed delicately into your uterus.

Step 4: Monitoring and support 

In the fortnight after your embryo transfer, your hormone levels will be monitored and supported using medication to ensure the environment remains ideal to sustain embryo implantation.  You must continue your medication until the outcome of your cycle is determined via a blood test. 

What are the risks involved with a Frozen Embryo Transfer? 

The risks associated with a frozen embryo transfer are minimal, but will depend on whether your Specialist has organised a natural FET cycle or a stimulated FET cycle for you.   

The risks from a stimulated FET cycle are minimal compared to an IVF/ICSI cycle, as very small doses of medication are used to prepare the endometrium for transfer of the embryo.   

Rarely if the endometrium fails to develop, then the cycle is cancelled and you will be reassessed as to treatment with a different stimulation protocol in your next FET cycle.  

Whilst Fertility North uses the most reliable and robust form of embryo freezing (vitrification), some embryos are too delicate to survive the freezing and thawing process, so the Embryology staff will keep you well informed about the status of your embryos!  

How we can help you?  

Fertility North is proud of its outstanding FET success rates.  Your Fertility North Specialist can discuss your eligibility for a frozen embryo transfer and together with you, will devise the treatment protocol most likely to achieve success.  

If you would like to talk to one of our Doctors, or any of our team about your FET treatment options, please don’t hesitate get in touch.  

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