Protecting and preserving fertility is a new way of empowering reproductive choice. The fertility of youth is no longer a limited resource, constrained by age. Women can now pursue their reproductive lives at their own pace, rather than according to the obligations of biology. Reproductive choice means having children when you want them, rather than when you must have them.
Fertility preservation, specifically egg freezing, is changing the way we think about building families. Through fertility preservation, eggs can be stored and saved for use a later.
The potential of fertility preservation replaces the tick of the biological clock
The tick-tock of the biological clock influenced reproductive choice in the last decades. The sacrifice of delaying family while assembling a career, home, and relationship worked in an economic sense. It did not, however, fit well with the designs of biology.
Eggs work best at a young age, when there are more of them, and they are more vital. The best pregnancy rates occur in women ages 18-30. With declining egg numbers and egg quality, pregnancy rates are lower in older age groups, while miscarriage rates and chromosome defects become more common.
Biology wastes eggs
The limit of egg quantity and quality is a consequence of our biology. From mid-gestation through menopause, there is a continuous stream of egg follicles that grow to a certain stage and then are lost. This pool of eggs is never replenished. Each woman is born with a set number of eggs (over a million), and by puberty perhaps 300,000 remain. Ovulation will happen only 500 times in a womans reproductive years. and will result in a child less than 1% of the time. From start (gestation) to finish (menopause), 1 in a million eggs results in a child. This constant and dynamic process of decline continues through the reproductive years, uninterrupted by birth control pills, pregnancy or ovulation.
Fertility preservation provides the potential for protection against future infertility
Fertility preservation is a relatively simple process. The first step is for a woman to see her fertility doctor for an ultrasound and physical exam. On ultrasound the ovaries are measured and the number of follicles determined. A treatment calendar with a schedule of injectable fertility drugs is initiated.
Using fertility medications for approximately ten days, multiple eggs begin to mature in the ovaries. Under sedation, the eggs are retrieved, a process that takes about 10-15 minutes. The eggs are then cryopreserved and placed in frozen storage.
At a later time, the eggs can be thawed, inseminated with sperm (ICSI is recommended), and the embryo(s) created transferred back into the uterus to develop into a pregnancy.
Technology of Fertility Preservation is improving
We are continuing to optimize the outcomes of oocyte cryopreservation. In a series of women under age 30 where eggs were cryopreserved, egg survival was 88%. Over half of the eggs fertilized, and two thirds of transfers resulted in pregnancy. As of January 2011 Pacific Fertility Center has 8 delivered babies from cryopreserved eggs.
The limits of biology continue to constrain outcomes of those eggs that survive. Not all eggs have the capacity to produce a viable embryo. This variable is very age dependent. In a healthy woman under the age of 30, approximately one third of her eggs(33%) are capable of producing a viable embryo. In women over the age 40, this ratio changes to one in twenty (5%).
Fertility Preservation: reproductive choice
The message is this: Fertility is optimal in your youth. If you have not started your family, you should consider freezing your eggs for use in the future.
-Philip Chenette, M.D.