FER or FET (Frozen Embryo Transfer) (freezing embryos that can be used later)
The eggs that have been frozen in connection with your IVF treatment can be used for transfer.
You can have this done either in your natural or a stimulated cycle:
1. In your natural cycle you will be scanned between day 9 and day 12, depending on the length of the cycle. When the follicle is large enough, you will take an ovulation-inducing injection and start taking progesterone 3 days later. The transfer occurs 2 to 5 days after you start using progesterone, depending on whether you have an embryo or a blastocyst.
2. In a stimulated cycle with estradiol, take tablets for about 8-12 days from the second day of bleeding. After that, you will be scanned to measure the width of the lining of the uterus. When it’s thick enough, you start taking progesterone. The transfer will take place 3 to 5 days later, depending on whether you have an embryo or a blastocyst.
One or two eggs
In the case of a transfer, you decide in consultation with the doctor whether you will have one or two eggs inserted. The criteria for this are your age, weight, your fertility, and any illness that means that a twin pregnancy would be harmful to your health.
For young patients under 37 years of age, only one egg is usually recommended for the first two attempts.
A very minor procedure that only takes a few minutes and is usually not painful. The egg is placed in the lining of the uterus with a small, thin catheter. You will then continue to use vaginal progesterone and take the pregnancy test about 12-14 days after the transfer.
The transfer takes place either in the embryo stage (day 2-3) or in the blastocyst stage (day 5).
Approximately 25% of the fertilized eggs develop into blastocysts. Whether the eggs can be developed in the laboratory until day 5 depends on your age and the number of fertilized eggs.
For women who have few eggs of low quality, it may be preferable to transfer the fertilized eggs on the second or third day, as the eggs can get into the natural uterine environment faster and have best chances of survival there. The excess eggs can of course be frozen for up to 5 years and or until the woman turns 46.
For both ICSI and IVF, there must always be a one-month break between attempts, unless the eggs are frozen.
You don’t have to take breaks between inseminations.