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Frozen Embryo Replacement Cycle (FER)

This procedure uses previously frozen embryos for treatments.

Spare good quality embryos from your IVF treatment that would otherwise be disposed of are kept and frozen for future use. This allows a couple to have up to three or four cycles from the same egg collection.

Frozen embryo replacements can be managed either as a natural cycle or in a stimulated (controlled) cycle. In a natural cycle no drugs are given. Ultrasound scans are carried out to monitor the cycle in order to pinpoint the best time for embryo replacement, ie, when ovulation has occurred and when the endometrium (lining of the womb) is suitably thickened and implantation is most likely.

In a stimulated cycle you would need to take medication to control the timing of your ovulation. Ultrasound scans are used to monitor the cycle and an injection is given to induce ovulation - this is done when a leading follicle is considered the right size and the endometrium is the right thickness.

The timing of the transfer is important. The embryos are thawed in conjunction with the cycle and are replaced three to five days after ovulation. Our Embryology team will inform you of how well your embryos have survived the thawing process and if they are of good enough quality for your transfer to take place. Sometimes embryos do not survive the thawing process. If this happens, we will book a review appointment for you with one of our specialists to discuss your options going forward.

The embryo transfer is similar to a smear test. It may cause some minimal discomfort. The culture medium containing one or two embryos is loaded into a thin catheter with a syringe on the end. The doctor carefully guides the catheter through the vagina and cervix, and deposits the embryo(s) into the uterus. Implantation begins three to four days later.

After the embryo transfer, cyclogest pessaries, which contain the hormone progesterone, will be prescribed. These are vaginal pessaries which help to support the lining of the womb. You will be given specific instructions on how to use these by the nurses.


Click here to read more about Embryo Freezing.


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