Female patients may choose to freeze their unfertilized eggs, ‘oocytes’, for future use because if she is not ready for family yet. Cryopreserved eggs can be thawed and available for fertilization by either a partner’s sperm or donated sperm in the future.
Unlike men, as women age, our odds of conceiving decline significantly. This phenomenon is largely attributed to reproductive aging, in which both the quantity and quality of eggs, or ovarian reserve, decline over time.
A baby girl has 1-2 million eggs when she is born. Egg number keeps decreasing until exhausted during menopause. When a female enters her late 30s, her egg number decreases significantly, even more in her early 40s.
Egg quality also declines with aging, which means when a female enters her late 30s, the proportions of abnormal eggs which could not result in a healthy pregnancy are getting higher and higher. Therefore, it will be more and more difficult for women to conceive naturally with aging. Also, women are facing higher and higher miscarriage rate caused by abnormal pregnancies with aging.
Oocyte vitrification is the technique we used in preserving women’s oocytes. Vitrification is a “flash freezing” method that cools cells from 98ºF to -320 ºF in less than 1 second, so that they become “glass-like” or “vitrified.” “Flash freezing” can avoid destructive ice crystal formation during the freezing process. Typically 95% of vitrified oocytes survive the process.