Embryo freezing is a procedure that allows people to store embryos for later use. A person can also freeze eggs, which are not fertilized. An embryo forms after fertilization and after the cells start to divide. Embryo freezing is a process of preserving the eggs, sperm and embryos for future use. It can be done before in vitro fertilization (IVF) or after. The process is usually done by a fertility specialist.
A woman has two ovaries that contain egg cells. These cells are called oocytes or ova. These eggs are stored in small sacs called follicles, which are located on the outside surface of the ovaries. When a woman’s menstrual cycle begins, one egg cell from each follicle will be released into her fallopian tube. This release is called ovulation. If no pregnancy occurs, then these eggs will die in about 2-3 days and be reabsorbed into the body as new tissue to make up for monthly cycles lost during menstruation
With an increased risk of cancer with age, many women are choosing to freeze their eggs in order to preserve their fertility. This procedure can reduce the stress and anxiety that comes with the possibility of having children late in life. The success rates for egg freezing are around 30% which may not be a feasible option for everyone.
Freezing embryos created during IVF before transferring them back to the patient has become increasingly common as freezing techniques have improved. Oocyte cryopreservation has advanced greatly over the past few years, with improved overall success of eggs surviving the freezing process.
Egg Freezing Process
The assessment would include blood tests and pelvic ultrasound. This will also help to determine the necessary dose of medications. Ovarian stimulation is carried out in the same manner that is used with in vitro fertilization (IVF), using injectable hormonal medications. Following the stimulation, the oocytes and the surrounding fluid in the ovarian follicles are aspirated vaginally while under sedation.
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, and this is achieved by ultra-rapid cooling into liquid nitrogen where they can be stored.
When the woman is ready to use the frozen eggs to achieve pregnancy, these cryopreserved eggs are placed in warming solution and assessed.
The main difference between egg freezing and embryo freezing is that the eggs are frozen before fertilization in egg freezing method whereas eggs are frozen after fertilization in embryo freezing method. Furthermore, frozen eggs have a less potential to survive while embryos have higher survival rates during freezing and the following thawing process.
