When patients begin IVF, they are usually focused on the immediate future and their hope for a child. But in many cases, successful treatment results in the possibility of having another child at a later time through frozen embryo transfer (FET).
In vitro fertilization can result in more than one fertilized egg. After the successful transfer of the embryo(s) during that IVF cycle, patients have the option of preserving suitable embryos that remain with cryopreservation, or freezing (known as vitrification). When the couple is ready, a preserved embryo can be transferred via frozen embryo transfer, or FET.
How Does It Work?
Before starting an FET cycle, the physician will assess the patient’s hormone status and the uterus to ensure there are no abnormalities that have developed since the first IVF cycle. Next, the patient will be prescribed medications to increase uterine lining thickness, preparing it for implantation.
There are two protocols used for FET cycles. Both use hormones, including estrogen and progesterone, to prepare the uterus for embryo implantation. Embryo transfer is usually done on either the 4th or 6th day of progesterone, depending on which day following fertilization the embryo had been frozen.
There is no data that any one protocol works better than another and the protocol chosen is based upon your specific needs.
Previously-frozen embryos have a greater than 95% survival rate and pregnancy rates from frozen embryos are excellent.
How Long Can My Embryos Be Stored?
Embryo freezing has been performed since the 1980’s. It is not known how long embryos can be safely frozen, although there have been successful pregnancies even after being frozen for 10 years. Most likely they can be stored indefinitely.
A careful inventory is kept for all embryos in storage by our laboratory. The charge for embryo freezing includes the cost of storage for one year. Patients are then billed annually. It is the patient’s responsibility to notify us of any change in address.
What are the options if I no longer want to keep frozen embryos in storage?
Patients that no longer wish to store their frozen embryos have several options, which we can discuss with you if that time should arise.