Human oocyte cryopreservation (egg freezing) is a process in reproductive medicine in which a woman's eggs are preserved out of socio-political reasons. [1] This procedure allows a young woman (at least before the age of 35) to extract and freeze her eggs in order to use them at an advanced age when she wants to become pregnant and increase the chances of a healthy child. [2] Basically, for the harvest of eggs the same method as in the in vitro fertilization is used. [IN VITRO FERTILIZATION]

While male gametes (sperm) mature on a daily basis, the number of female gametes (oocytes) is inherent by birth. The maximum amount of 6.000.000 eggs is reached during the 5th fetal month, following birth the number drops to 40.000 to 50.000 and upon puberty there are 20.000 eggs left. [3] At an advanced age, the chance of genetic mutations increases due to the natural aging process of egg cells. In case of pregnancy, the child may suffer serious handicaps. [4]

In order to prevent this problem, reproductive medicine invented egg freezing. This technique has already been for a long time out of medical reasons, for instance, when women diagnosed with cancer have not yet begun chemotherapy or radiotherapy. [5] [6]

First, hormone injections stimulate the ovaries to ripen multiple eggs. When they are mature, they are subsequently removed from the body by transvaginal oocyte retrieval. The procedure is usually conducted under sedation. Then, the eggs are immediately frozen. According to the gynecologist and expert on the treatment Prof. Dr. Frank Nawroth, at least 10 to 15 cells should be removed. These eggs are quick-frozen in liquid nitrogen at a temperature of -196 degrees Celsius and stored up to 15 years. When the eggs are thawed, around 85% of them survive the process and immediately have to be fertilized by sperm. However, only 8 to 10% actually implant in the uterus. [4] [5] [7] Possible complications are equivalent to those mentioned for in vitro fertilization.

In 2014, egg freezing became first known in public since companies like Apple or Facebook officially stated to pay the costs of the treatment (around $ 20.000) as part of the family program. [1] Ethically, the procedure is highly controversial because the hormonal treatment as well as the retrieval and implantation of eggs put a physical strain on women. Instead of finding ways to reconcile children with career, the "child problem" is postponed to the future. To date, it's unclear whether there have occurred special risks for "egg-frozen children" since there is no long-term data available. [2] [5] [7]

Egg freezing seems to offer an interesting option for women who want to combine their career chances with fertility preservation. But the issue of women's reproductive rights remains. To what extent is society or an employer allowed to decide the right time of birth for a woman? Can mothers at an advanced age be held responsible for not freezing their eggs? While these questions are still to be answered and discussed in media, the numbers of procedures rises annually and the egg freezing business increases steadily. [2] [5] [6] [7]