Freezing eggs or egg preservation is a procedure in which a woman’s oocytes (eggs) are retrieved, frozen and stored. The purpose of the procedure is to have the frozen eggs thawed, fertilized with semen, and transferred to the uterus as an embryo to facilitate a pregnancy in the future.
Egg freezing is usually done in the following cases:
- If the woman would like to preserve her future ability to have children, either because she does not yet have a partner, or for other personal or medical reasons.
- If the woman has a family history of premature menopause.
- If the woman has a history of ovarian surgery or chemotherapy with a fewer eggs available in her later years.
- A fertility specialist will perform an assessment of the ovarian reserve to estimate the potential yield of oocytes prior to ovarian stimulation cycle.
- The assessment would include blood tests and pelvic ultrasound, which helps to determine the necessary dose of medications. Ovarian stimulation is carried out in the same manner as that of in-vitro fertilization (IVF), using injectable hormonal medications. Following the stimulation, the oocytes are aspirated vaginally under anaesthesia.
- The maturity of the eggs is assessed under the microscope, and those that are mature are cryopreserved. Currently, vitrification is the method of choice for cryopreserving oocytes. The frozen eggs may be stored for many years without significant deterioration.
- About 70-80% of oocytes survive freezing and thawing, and 50-70% of them get successfully fertilized.
- The chance of becoming pregnant after implantation is approximately 30-35%, depending on your age at the time of egg freezing and other associated conditions. The older you are at the time of egg freezing, the lower the likelihood that you’ll have a live birth in the future.
- Pregnancy rates might be lower when frozen eggs are used, when compared to fresh or frozen embryos.