The use of cryopreservation in fertility treatments has been widely applied since the 1980s when pregnancy and live birth was first achieved from a frozen and thawed embryo. Since that time, reproductive technology continues to advance and now, in addition to embryo cryopreservation, egg cryopreservation is also becoming more common. New to reproductive technology, egg freezing is giving additional choices to couples trying to conceive or wishing to extend or preserve their time of conception. Having been recently developed, a relatively few number of people have yet chosen to have their eggs thawed yet although early results show a better than 20% success rate.
What is Embryo Cryopreservation?
Embryo cryopreservation, or embryo freezing, is a commonly used form of assisted conception treatment for couples experiencing fertility problems. Typically, to assure the highest possibility of success, more embryos are created than will be used in one IVF cycle. When there are embryos that are not used in an IVF treatment, many couples opt to preserve them for possible use in a subsequent treatment cycle. In order to be preserved, the embryos undergo the following process:
- The embryos are placed in thin vials which resemble straws
- A preservation solution is added to the vile to protect the embryo
- The vials are stored in a controlled freezer containing liquid nitrogen
The Thawing Procedure
- The Embryo is brought to room temperature
- The embryo is cleaned of any preservation fluid
- The embryo is warmed to body temperature
The Transfer Procedure
- A thin catheter is gently guided through the cervix and into the uterus
- The embryo is transferred to the uterus
Many women report that the Frozen Embryo Transfer (FET) process is much less stressful than a “fresh” embryo transfer and many fertility specialists have much better results using embryo cryopreservation.
What is Egg Freezing?
Very new in reproductive technologies, egg freezing is offering new possibilities in couples trying to conceive. The egg freezing process is very much like the embryo cryopreservation process. In egg freezing, some of a woman’s eggs are collected to be frozen and used at a later date. Like in embryo cryopreservation, the eggs are stored in protective medium and frozen. Although so new that very little data has yet been obtained, the process is proving very promising. Already, 300 pregnancies have been achieved using the process. Typically, the process is considered for women 40 years old or younger. Though the principle is the same, there are some slight differences in the process which include:
- Some of the media used to process the eggs is different
- The eggs require a different cooling rate
- Egg freezing has not been around as long as embryo cryopreservation and long term data is not available
Preserving Fertility Options
Both embryo cryopreservation and egg freezing are options for those either having difficulty conceiving or those who wish to preserve fertility options and start a family at a later time.
