Frozen Embryo Transfer (FET)
Healthy embryos resulting from an IVF cycle but not transferred to the patient at the end of the cycle can be cryopreserved and stored. When the patient is ready to have another child, her embryo(s) are thawed and transferred to her uterus at the appropriate point in her menstrual cycle. This process is called a frozen embryo transfer (FET). A patient preparing for an FET has blood testing and ultrasound scans that enable her physician to identify the appropriate point in the patient's cycle to transfer the embryo(s). Some FET patients may also take hormone medication to prepare for the transfer.
FETs have high success rates and do not require a full IVF cycle. Some CRM patients may also undergo "natural" frozen embryo transfers, which require less or no hormone supplementation.
The FET Process
In a medicated (also commonly referred to as a "programmed" FET), the patient takes a course of hormone medication that ensures that the patient's endometrium (lining of the uterus) is prepared to receive the thawed embryo(s).
CRM patients routinely performs "natural" FETs by using blood testing and ultrasound to plan the embryo transfer. Natural FETs require minimal or no medication.
Transfer and Post-Transfer
When the physician judges that the FET patient's endometrium is approaching its peak receptivity, the embryo transfer is scheduled. On the day of the transfer, the patient's embryo(s) is thawed by Embryology Laboratory staff and transferred by the physician into the uterus. Embryo transfer is an outpatient procedure that does not require sedation and typically has no side effects.
After the transfer, the patient returns to CRM for testing, including a confirming pregnancy test. The patient transitions to the care of an obstetrician when the fetal heartbeat is detected, around week seven of the pregnancy.