Age and Fertility – The Impact of Age on Female Fertility
What is the Biologic Clock?
The “Biologic Clock” is a collective term that refers to the incessant winding down of the reproductive organs along with the physiologic wear and tear occurring throughout the normal aging process.
Few topics related to infertility arouse so much anxiety and confusion as the effect of aging on fertility and ultimately pregnancy. It is a source of internal stress that can be overwhelming as a woman worries about her “biologic clock”, which can sometimes lead to additional medical problems like anxiety and depression. During this time it can be helpful to become well informed in order to best understand how the physiologic process of aging affects fertility.
What Happens to Reproduction as Women Age?
Although it is not frequently discussed, reproduction in humans is very inefficient at best. Even during peak human fertility in the teen years and the 20’s, the chance of pregnancy is about 20% per month, assuming a woman has regular ovulation, with open Fallopian tubes and a partner with normal sperm production. Dysfunction in any of these factors can lead to infertility or may prolong the time needed to become pregnant. Additional gynecologic problems such as endometriosis, pelvic scarring and uterine fibroid tumors can occur at any time and may interfere with the normal process of egg entry into the Fallopian tubes or failed implantation of the embryo.
How does Aging Affect Human Eggs (Oocytes)?
One of life’s greatest ironies is that just at the right time when a woman is prepared emotionally and personally to begin her family, she may be confronted by the obstacles associated with infertility (life is just not fair!)
Note that the terms “eggs” and “oocytes” will be used interchangeably in this discussion. At birth, most women (but not all) are born with about 2 million oocytes (eggs) that are stored in their ovaries. Each egg is a microscopic, fluid filled cell lying in a protective capsule called a follicle, which in turn is located within the ovaries. Each oocyte is formed with a pre-determined lifespan that cannot be altered and may be as brief as a few days or up to many years. From the time of birth until the menopause there is a natural, unrelenting loss or attrition of the oocyte number as they are eliminated from the resting pool. The magnitude of egg loss is truly staggering, such that by adolescence, 90% of the eggs available for ovulation has been lost, leaving about 100,000 from the original 2 million at birth (see graph 1). Unlike ongoing fresh sperm production in men, there is no new formation of fresh, healthy eggs in women. (again, life is not fair).
Graph 1: Natural Oocyte Decline in Women
Changes in the Internal Structure of Aging Eggs
The cytoplasmic fluid within the egg contains many tiny organelles and the so called cytoskeleton. Spontaneous deterioration of the egg’s internal protein structures, like the mitochondria, will cause a disturbance in the normal steps of the fertilization process. This may lead to the development of suboptimal embryos that fail to develop normally, leading to implantation failure or loss of the pregnancy (miscarriage) during the first few weeks.
Chromosomal and Genetic Abnormalities Associated with Aging
Additional age-related changes are structural defects in the chromosomes, microscopic sticks of genetic information inside the egg nucleus. They contain vital DNA information necessary for the development of a normal child. An example of a genetic mutation is the disease called Cystic Fibrosis.
Furthermore, numerical abnormalities in the number of chromosomes can occur when entire chromosomes can be lost, duplicated or become fragmented. An example of these types of chromosomal errors is Down Syndrome where one extra chromosome develops in the 21st pair of chromosomes. This may lead to a birth defect or an early pregnancy loss.
THE NATURAL PROCESS OF EGG SELECTION
Only the Strongest Egg Survives
Each month, at the start of a new menstrual cycle, the ovaries initiate recruitment of 40 to 50 eggs from the resting oocyte pool. An elimination process begins such that by ovulation time 14 days later, only the most favorable oocyte is released each month.
Even with this rigorous selection, an oocyte can still have undetectable abnormalities, which can slip by nature’s protective screening mechanisms. These checks and balances help minimize abnormal pregnancies, insuring that only the healthiest embryos can implant. Unsuitable eggs may fail to become fertilized or not divide properly leading to failed implantation or abortion.
Unfortunately, the changes discussed above cannot be reversed and with advancing age, even IVF may not overcome the egg abnormalities. In these cases the physician may recommend the use of donor eggs to bring about a healthy pregnancy and a happy family.
USING FROZEN DONOR EGGS TO OVERCOME FEMALE INFERTILITY
Donor Eggs Rewind the Biologic Clock
When age-related infertility is diagnosed, even a well planned IVF cycle may be ineffective in overcoming suboptimal egg quality and a negative outcome. This illustrates the overwhelming importance of egg vitality in achieving a successful pregnancy. On these occasions, it may be helpful to recall that the treatment outcome of all fertility treatments is the birth of a healthy baby and happy parents. With this goal in mind, it becomes clear that different options may need to be explored to achieving the desired end result. While some patients accept adoption, others are excited about giving birth to their child by using donor eggs and the male partner’s sperm.
What Are the Advantages of Using Frozen Donor Eggs?
With the use of frozen donor eggs in a fertility setting, many advantages become apparent. Among the most significant benefits are:
- Intended parents can select frozen eggs from the donor of their choice in the privacy of home by using our on-line donor catalogue.
- There is no time lost in searching for a donor who may live in a distant location and will incur travel or hotel expenses.
- There is no need for synchronization of the recipient’s uterus with the donor’s ovarian cycle, saving time and money in the preparation process.
- There is no risk of medication errors or non-compliance by the donor which can result in cancellation of the cycle.
- There is no waiting time for the donor to become available. Recipient mothers can begin the process immediately.
- Egg donors have been carefully screened medically and psychologically according to FDA criteria.
Risks of Using Frozen Eggs
It is known that all medical procedure and treatments carry some element of risk which can be reviewed by your medical provider. All our frozen egg treatment cycles are conducted under Investigational Review Board (IRB) supervision. An IRB is a group of professionals who determine that new and investigational treatments are conducted under strict overview. Our doctors and scientists have completed a special course on the ethical management of medical treatment for human subjects. We maintain close documentation of any complications, which are reported to the IRB.
Frozen Egg Bank, Inc. is constantly monitoring the outcome of our frozen egg technology and searching for ways to improve the pregnancy success rates. We actively pursue laboratory and clinical research to maintain the accuracy and purity of our techniques. We invite all our patients who have used frozen eggs to enroll in our birth registry, which tracks the health of the children up to 12 months of age.