What is a Frozen Embryo Transfer?
A frozen embryo transfer (FET) is a cycle in which frozen embryos from a previous IVF or donor egg cycle are thawed and then transferred into a woman’s uterus to help achieve pregnancy.
Frozen embryo transfers (FET) are becoming as common as fresh embryo transfers. There are several reasons why a patient may choose or be encouraged by their doctor to consider a frozen embryo transfer. This type of transfer:
- Gives potential parents the flexibility to plan
- Allows patients to save high-quality embryos at a younger age and do implantation later
- Enables couples facing extraordinary circumstances, such as cancer treatments, the chance to pursue having children after interfering treatments are completed
- Offers the chance for preimplantation genetic testing (PGT) testing, as it takes 2-4 weeks to get results back
With an FET cycle (versus a fresh embryo transfer), the patient can select her transfer date and schedule monitoring visits well in advance. If using an egg donor, the recipient does not have to sync her cycle with the donor, which can sometimes be a frustrating process. If PGT-A is performed, the embryologist is also able to choose only chromosomally normal embryos for transfer, increasing the odds of a healthy pregnancy.
Preparing for a Frozen Embryo Transfer Cycle
During the FET cycle, embryos are thawed and placed into a patient’s uterus. The process is timed with a menstrual cycle to best support a pregnancy.
Uterine receptivity plays a large role in embryo implantation. Before the FET cycle, the prospective mother will take medication to reduce ovarian activity. Estrogen pills or injections (of a hormone called leuprolide) may be prescribed by the participating clinic to build up the lining of the uterus to prepare for the embryo implantation, then a progesterone treatment is given to make the uterus receptive to the embryo. While taking these hormones, a patient will have blood tests and ultrasound exams to help monitor how their body responds to hormone treatment.
Occasionally, it takes longer than expected for the endometrium to thicken after taking hormones. This may change the expected date of the FET. Extra hormones and more monitoring may sometimes be needed.
What to Expect at Your Frozen Embryo Transfer Procedure
An embryo transfer is similar to having a pap smear. Patients may experience some minor discomfort when the speculum is inserted or when the catheter is passed through their cervix.
When the uterus is ready, the doctor inserts a catheter into the vagina through the cervix and into the uterus. Using a syringe, the thawed embryo is carefully injected into the uterus, along with a small amount of fluid.
Afterward, the embryologist will examine the catheter under a microscope to ensure the embryo is no longer inside. Follow-up instructions are given.
About 14 days after the embryo transfer, a blood pregnancy test will confirm if the procedure was successful. When pregnant, the mother should keep using estradiol and progesterone until instructed to stop by the physician.
The embryo transfer procedure may cause some cramping, discomfort, and a small amount of bleeding. Very rarely, an infection may occur from the catheter, which can be treated with antibiotics.
Frozen Embryo Transfer Success Rate
Today’s standard practice is to transfer one embryo at a time. This minimizes the chance of multiples while maintaining the same cumulative live birth rates (per retrieval) from an IVF cycle.
Thanks to vitrification, a flash-freezing methodology, frozen and thawed embryos have the ability to maintain their quality to a high degree. Embryo quality is now nearly identical for both fresh and frozen embryos.
While there is the possibility embryos may not survive the freezing/thawing process, the risk is very minimal as over 95% of frozen embryos survive the thawing process.
Embryo transfer with thawed frozen embryos is now more widely used. Pregnancy rates are similar, and sometimes even higher, than with embryos that have not been frozen. According to a study published in the New England Journal of Medicine, live birth rates and pregnancy were similar among women using either frozen or fresh embryos.
What to do After a Frozen Embryo Transfer
Go home and have a relaxing night. Some women have a second round of acupuncture just after their transfer, as studies published in Fertility and Sterility indicate that acupuncture performed before and after IVF embryo transfer has increased the rates of pregnancy by as much as 35-50%.
Patients may resume their normal routines and stay active but should avoid strenuous exercise. They should abstain from sex and avoid extreme temperatures, meaning no hot baths, saunas or heating pads. Stay as relaxed as possible, get good sleep and behave as if you’re pregnant.
Here at Atlantic Shared Beginnings in Raleigh, North Carolina, we provide the knowledge and support our clients need for their unique fertility journey. Your health, well-being, and safety will always be at the heart of everything we do. If you are considering donor eggs, we are here to answer your questions and listen. Schedule your free consultation today.