Frozen Embryo Transfer

What is the frozen embryo transfer cycle (FET)?

The cycle where one or more frozen embryos are thawed and transferred to the uterus to achieve pregnancy is known as a frozen embryo transfer cycle.

The process of frozen embryo transfer

This process of transferring the embryos to the uterus can be done either in the natural cycle or in a hormone- controlled cycle.

Natural cycle

Who is it for?

Women who have regular menstrual cycles and can easily track their ovulation are suitable for frozen embryo transfer in a natural cycle.

How does it work?

Your cycle is monitored with ultrasound scans and blood tests to check endometrial development. You will have to track your ovulation at home as well. Based on when ovulation naturally occurs and the stage in which your embryos were frozen in(blastocyst stage or cleavage stage), the date for embryo transfer is scheduled.

Hormone replacement therapy(HRT) cycle

Who is it for?

For women who don’t have regular periods, have ovulatory problems or need to have the embryo transfer at a particular date, the HRT process is suggested to have the frozen embryo transfer.

How does it work?

Hormones oestrogen and progesterone are prescribed to mimic the body’s cycle and to develop your endometrium to the right stage. Regular ultrasound scans and blood tests are done regularly to monitor your progress. Usually the embryos are transferred 5 days after starting progesterone but this can vary depending on the stage at which your embryos were frozen and your individual development.

When are the embryos thawed?

The embryos are thawed a few hours before the transfer. After thawing, the embryo is placed in a dish and washed with culture media before placing it in the incubator to await the transfer procedure. Cleavage stage embryos might be developed to blastocyst stage in which case they are left in the incubator after washing with culture media for a few more days. Generally 95% of blastocyst stage embryos and 80-85% of cleavage stage embryos survive the thawing process.

How are the embryos transferred?

No anesthesia is required for this process unless it has been difficult for you in the past or if you prefer to have it. The embryologist will select the best embryo(s) for transfer. The process is carried out in a dedicated procedure room. Mild discomfort may be experienced by some women. The practitioner cleans the vagina by inserting a speculum in the vagina. After that a catheter is inserted through the cervix into the uterus to place the embryo(s) under ultrasound guidance. You are required to have a full bladder.

What is after embryo transfer?

Women may experience some light cramping and very occasionally spotting and vaginal discharge after the cramping. You are advised to take it easy and avoid hot baths, saunas, exercise, sexual intercourse, swimming, steam rooms, drinking alcohol and smoking. Be sure to take your supplements and folic acid as recommended by your expert consultant and follow the instructions given by your fertility team if taking hormones. Depending on whether you had blastocyst or cleavage stage transfer, your pregnancy test will be scheduled for 12-15 days after the embryo transfer.