Assisted reproductive technology is a term designating a wide range of methods to induce pregnancy employing artificial means. The best known assisted reproductive technology is in vitro fertilization. Cryopreservation is a method that involves freezing eggs, sperm or an embryo and using it at a later date.
Cryopreservation is a relatively new procedure used in assisted reproductive technology, and in involves the freezing of eggs, sperm or a viable embryo, which may be used at a different time.
Sperm and eggs have been frozen and used during in vitro fertilization for a long time, resulting in many healthy pregnancies. The cryopreservation of an embryo and the very first pregnancy resulting from such a method was reported in the early 1980s. Ever since, the number of frozen embryos leading to successful pregnancies has multiplied and presently, cryopreservation of embryos is very commonly used by couples.
The cells are frozen and kept in liquid nitrogen. Theoretically, the frozen cells can be kept for an infinite amount of time and they should be viable at any point after being thawed. The eggs or sperm may be from the couple undergoing IVF, or these cells may be from donors that are carefully selected and go through a screening process, to ensure that the eggs and the sperm are of good quality and the chances of pregnancy are increased.
Who Can Benefit from Cryopreservation
Cryopreservation can be used in patients that due to personal or medical reasons want to postpone a pregnancy.
Many patients that use cryopreservation are doing this due to the fact that they have a limited number of eggs left (due to age), but they want to have a child at some point. The cryopreservation method will allow older women to have children, which are less likely to have birth defects. Women over the age of 40 have high chances of getting babies with a birth defect, due to the fact that the best ovules are eliminated during the younger years and the remaining ovules may be flawed.
Other women that resort to cryopreservation are going under treatment with chemo drugs or radiation therapy, which can affect the ovaries, so they may not be able to have children again.
There are also couples that use cryopreservation, freezing an embryo that will be used in a few years' time, due to career or personal choice.
Many times, during IVF, several viable embryos may result and some couples choose to freeze these and use them, or donate them for couples that are infertile. Patients or couples interested in cryopreservation are tested and will undergo a longer treatment, especially women, to ensure that the quality of the eggs is acceptable.
Risks of Cryopreservation
The cryopreservation may not always result in a pregnancy or may result in a pregnancy, but the fetus may be aborted. The freezing is generally safe, but in some cases, the cells can be damaged, resulting in birth defects. Several cases of multiple pregnancies after the use of cryopreservation have been reported.