Frozen Embryo Transfer – All the Details You Need to Know
A Frozen Embryo Transfer (FET), is one of the most popular IVF treatments, especially among women 35 years old or younger, with more than 60% chance of pregnancy. However, this method is found to be particularly successful and suitable for several other cases as well (more details to follow). This guide will give you detailed information about FET, including the standard procedure, the various options available, and the possible risks involved, among many others, so you know as much as possible about FET, for when the time comes.
What is an embryo transfer?
It is the very last phase in the IVF treatment procedure, where we transfer the fertilised egg in the female partner’s uterus to hopefully implant, grow into a fetus, and lead to the birth of a healthy baby. Before the embryo transfer, the fertilised eggs are left to develop for several days in an advanced incubator, where they are carefully monitored to ensure all goes as planned and expected. At this point, you have many options as to which embryo transfer method to choose. One of the most popular ones is frozen embryo transfer or FET in short.
What is Frozen Embryo Transfer?
In FET, embryos (aka donor embryos) created in a full IVF cycle (and not used in the conventional IVF cycle) are thawed (cryopreserved) so they can later be transferred to a uterus. It should be noted that frozen eggs have many possibilities. For example, they can be donated to couples facing fertility issues where the fertilisation of the female partner eggs with the male partner sperm cannot produce viable embryos.
Frozen vs. Fresh Embryo Transfer
Some IVF clinics prefer to use fresh embryos rather than thawed ones. Our IVF Specialists at the Cyprus IVF Clinic take factors like ovulatory vs. anovulatory status, stimulation response, and age into account before they make the best recommendation per patient – to us, each case is different and requires a customised approach and treatment protocol. That aside, there are no major deviations between the two methods regarding the percentage of live births following an embryo transfer using fresh and frozen embryos. The differences are insignificant. Nevertheless, frozen embryo transfers are more preferred for the convenience and practicality they offer (i.e., you can freeze an egg or embryo and use it at a later time). That being said, theories claim that embryos that have been cryopreserved and survive the process are stronger than the ones that don’t. This allows fertility experts to distinguish the best embryos for FET - the ones that could lead to a healthy pregnancy.
Note: There are cases when we recommend fresh embryo transfers (i.e., in older patients whose embryos did not make it to the lab testing or younger patients with no suspected chromosomal problems). We may also consider an elective single frozen embryo transfer (eSET), where one fresh embryo is transferred while the other ones that result from the IVF cycle are cryopreserved, depending on the patient’s case.
When is Frozen Embryo Transfer Recommended?
Specific circumstances and health conditions call for FET to help conceive. Some of the most important ones are as follows:
1. You want to keep the extra embryos for future use– You may wish to have another child in the future but would like a more cost-effective solution to having another fresh cycle. You can freeze the embryos that are not used in your IVF cycle and choose to have them transferred to your uterus if you decide to give your IVF-conceived offspring a brother or sister.
2. You are using PGT (Preimplantation Genetic Testing) – Many times, a frozen embryo transfer is part of PGT. This is another assisted reproductive technology also called PGS – Preimplantation Genetic Screening – where embryos are screened for specific genetic defects or diseases by conducting a biopsy on Day 3 or Day 5 eggs (post fertilisation). You may be able to do a frozen embryo transfer using untested embryos that were not used in your PGT. Or, you may simply have frozen embryos already because you thawed them for the PGT testing.
3. You have cryopreserved your embryos after an IVF cycle – Transferring multiple embryos increases the risk of getting pregnant with triplets or quadruplets (aka high-order multiple pregnancies). In such cases, and only if you have a good prognosis, we recommend an elective single embryo transfer, where we transfer one embryo and freeze the other ones that you got from IVF. If a fresh embryo transfer is unsuccessful, you can either undergo a second fresh embryo transfer or transfer cryopreserved embryos (one or two, not more).
4. You are at high risk of Ovarian Hyperstimulation Syndrome (OHSS) – OHSS is a condition related to fertility medications that can lead to (in extremely rare and severe cases) fertility loss and even death. If we determine that a patient is at high risk of OHSS before a fresh embryo transfer, we may cancel the fresh embryo transfer and freeze all the embryos. As soon as you have recovered from OHSS, which can take longer if you are pregnant (pregnancy may exacerbate OHSS), we schedule a frozen embryo transfer cycle.
5. You are using an embryo donor – If you decide to use the embryos of another woman (a donor from our donor database or a dear, healthy person of yours), your cycle will need to be a frozen embryo transfer. An embryo donor may also be another couple that wishes to donate their additional embryos to infertile couples.
6. Your FET has been cancelled – If you get the flu or have another illness after we have retrieved your eggs and before we transfer the embryos into your uterus, we may cancel the fresh embryo transfer. We may also recommend cryopreserving your embryos if the endometrial conditions (as we evaluate them on the ultrasound) do not look good. In this situation, we usually schedule a frozen embryo transfer IVF at a later date.
Frozen embryo transfer – The process
It should be noted that every single frozen embryo transfer is customised to the cycle of the intended female parent, which depends on the development of their uterine lining and how they respond to the medications (if any drugs are being used). As for the FET process, the steps included are described below. Note that embryo transfer is the final IVF stage, so we only explain what to expect during FET, not the entire IVF procedure from start to finish.
Step #1. The patient enters the designated transfer room at the Cyprus IVF Clinic (Your partner, doctor, embryologist, and nurse are all with you).
Step #2. Under sterile conditions, we administer light sedation (no anaesthesia needed) to help relax the uterine muscles and allow you to calm.
Step #3. A speculum is placed (vaginally) to enable us to have good visualisation of the cervix (you may feel some minor discomfort at this point).
Step #4. A transfer catheter is placed into the uterus (via the cervix) with the guidance of an ultrasound.
Step #5. Our embryologist loads the embryo into the transfer catheter and gently deposits it into the uterus.
Step #6. You are being left to rest for about 15 minutes.
Step #7. We give follow-up instructions and schedule bloodwork for 4-7 days after the frozen embryo transfer.
Step #8. A pregnancy test is done 10 days after the FET.
As you will realise yourself, a FET and a pap smear do not differ much. Concerning how the uterus is being prepared to accept the embryo for implantation, this is done via hormone medications. The first of two steps involve the suppression of the patient’s pituitary gland to minimise the chances of unexpected ovulation. During the second phase, hormone medication (estrogen and progesterone) is administered to duplicate the normal uterine function (the changes that take place within the uterus during a normal period).
Here is what a sample FET calendar looks like:
Day 1-9 (Estrogen)
Day 10 (Estrogen and monitoring)
Day 11-16 (Estrogen and progesterone)
Day 17 (Embryo transfer, estrogen, and progesterone)
Day 18-25 (Estrogen and progesterone)
Day 26 (Pregnancy test, estrogen, and progesterone)
Day 27-28 (Estrogen and progesterone)
Note that this is just an illustrative calendar. The exact days for each step may differ depending on the case. Day 1 is noted as the 1st day of stimulation drugs.
How to Prepare for a Frozen Embryo Transfer
Without a doubt, trying to conceive comes with a lot of emotional ups and downs. This is perfectly normal. The majority of our patients admit experiencing a rollercoaster of emotions during this life-changing phase. Women considering frozen embryo transfer, in particular, often find themselves struggling with dilemmas about whether they should go with donor embryos, how choosing FET will make them appear in the eyes of other people, etc. We feel you and stand by your side from the first moment you come to us for a consultation to the very last day of this wonderful journey, when you hold your baby in your arms. Remember that this is YOUR life, YOUR decisions, YOUR family, YOUR happiness. If having a FET feels right to you, then it is. You are only claiming what you deserve – a happy and fulfilling family life.
Ways to prepare for FET (and IVF, in general):
Practice mind-calming techniques, such as yoga or meditation.
Follow a fertility diet for at least 3 months before your FET that is rich in plant-based protein, folic acid, omega-3 fats, iron, fibre, vitamin B12 and vitamin D, if need.
Get rid of toxins (aka fertility cleansing) using liver and uterus-detoxifying herbs such as raspberry leaves, ginger root, milk thistle seed, yellow dock root, goldenseal root, and burdock root.
Fortify your uterine lining by consuming L-arginine and iron. This will also help prevent miscarriages.
Exercise (moderately).
Have a fertility massage that is believed to help strengthen the uterus and promote healthy blood circulation to the uterus.
Risks Involved in Frozen Embryo Transfers
A FET cycle does not have more risks than any other IVF treatment. Studies have evidenced that frozen embryo transfer cycles come with fewer risks than IV cycles. One major difference between FET and IVF, though, is that the first is NOT associated with increased risk for Ovarian Hyperstimulation Syndrome from the prescribed IVF fertility drugs simply because we do not use ovarian stimulation medications for this procedure.
Also, depending on the number of embryos that are transferred during FET, embryo transfer may increase the chance of multiple pregnancies. At the same time, the possibility of having an ectopic pregnancy is also high (as is with naturally-occurring pregnancies, of course).
Finally, with cryopreservation, some embryos may not survive a second biopsy if, say, the embryo PGT testing gives indeterminate results. And, if they do, the success rates are slightly lowered.
Final Thoughts
Waiting for a frozen embryo transfer is a critical moment in a couple’s life that is sprinkled with mixed feelings of anticipation, excitement, and agony for the unknown and the possibility of starting a family soon. Although a healthy pregnancy is dependent on several factors, knowing what to expect and how to prepare your body and mind for embryo transplantation are important aspects of this journey.
Remember that you are never alone. Cyprus IVF Clinic is right by your side all along the way, with experienced embryologists, geneticists, gynaecologists, and a highly qualified team of medical professionals ready to answer all your questions and caress your concerns. Together, we will find solutions to your fertility issues and help you achieve your dream of parenthood.
With an extensive aftercare programme, Cyprus IVF Clinic are ready to handle your every fertility need. Whatever your circumstances, please contact us today for advice and guidance on making the move towards IVF.
