By Dr Georgiana Tang, Medical Director and a specialist at City Fertility Sydney Liverpool and Sydney CBD
If you have been fortunate enough during an IVF cycle to have several eggs retrieved, then fertilised with sperm and good quality embryos created, the outcome will be spare embryos that you can choose to freeze for future use. This gives you the option to start with a Fresh Embryo Transfer, and if needed down the track, have a Frozen Embryo Transfer (FET).
Some ask why isn’t every embryo transfer cycle a fresh one and isn’t that a wiser option? The reality is that when women undertake an IVF cycle, the aim is to retrieve as many good-quality eggs as possible to optimise the chance of a successful pregnancy. IVF can be physically and emotionally challenging process and the fewer cycles you have to go through the better.
If you only relied on one egg or embryo per cycle, sadly not every egg will fertilise or go on to form a good-quality embryo. Having some spare eggs to fertilise and embryos to freeze is fortunate and extends your pregnancy potential. The success rates for fresh versus Frozen Embryo Transfers (FET) are also considered equal these days.
So what is the difference between having a Fresh Embryo Transfer compared to a Frozen Embryo Transfer? Here I explain a few of the facts for you.
What is a Fresh Embryo Transfer
- A Fresh Embryo Transfer normally takes place 2 to 5 days after egg pick up – you will be advised when the right time is.
- Prior to the transfer, the embryologist discusses with you which embryo will be transferred and why.
- The transfer may be performed with or without ultrasound guidance and takes place at the clinic.
- It is a simple medical procedure and normally requires no anaesthetic and you do not need to take the day off work.
What is a Frozen Embryo Transfer (FET)
- Following a Fresh Embryo Transfer, any remaining embryos can be frozen via a rapid freezing process called vitrification and stored for your future use in a Frozen Embryo Transfer (FET).
- The process for thawing embryos is very simple and involves removing the individual blastocyst from liquid nitrogen and replacing the cryoprotectant with water. This takes about 15 minutes.
- Preparation for a FET is a lot easier than a fresh embryo transfer as it does not involve the stimulation of the ovaries.
- A FET is all about timing it to take place at the correct stage in your cycle.
- The FET can be transferred in a natural cycle or in a controlled medicated cycle.
- The doctor will do a baseline check of your uterine lining at the start of the cycle and check it again a few days before transfer to ensure it is in optimum condition.
- The actual embryo transfer procedure on the day then replicates a fresh transfer and does not require sedation or medication.
- There is no time limit for using frozen embryos as they will remain as strong as were the day they were frozen.
- Finally, FET’s are considerably cheaper than a full IVF cycle as you are only going through a fraction of a full cycle.
