Age and Infertility
More and more women are having
their first child after the age of 35. This time also coincides with the
biological decline in fertility potential.* One of the most challenging
clinical scenarios is the impact of the aging egg on pregnancy chances. This
decline in fertility potential, or "ovarian reserve", is the natural
consequence of the aging process on human eggs.
Reproduction is
inherently inefficient. Out of every 100 couples under the age of 35
trying to conceive, approximately 20 will get pregnant in a given month.
Women have a set number of eggs when they are born, therefore as they age their
eggs become older and have an increased risk of chromosomal abnormalities. From
the time of birth to puberty, all eggs are "suspended in time". When menstrual
cycles begin, one egg is selected from this pool of eggs every month.
Once one egg is selected for a particular menstrual cycle, the LH
surge occurs and triggers completion of the ovulation process. Now the egg
can be fertilized. The length of time the egg waits for selection as a dominant
egg corresponds to the chronological age of the woman.
Lower
pregnancy rates and higher miscarriage rates are both the consequences of the
aging process, and reflective of a decline in egg quality (Table 1). Women
ovulate their healthiest eggs during their 20's and early 30's. By the mid 30's
the remaining eggs are of lower quality, and by the early 40s only eggs with
very low fertility potential are available for ovulation. This phenomenon is a
normal biological process, which neither fertility medications nor lifestyle
changes can halt.
A healthy egg has two functions necessary for a
successful pregnancy. First, it must have normal chromosomes, and second, it
must be able to combine its chromosomes with those of the sperm in a correct
and efficient manner to produce a normally dividing and growing embryo. While
eggs are suspended in time they are susceptible to injury which may
result in chromosomally abnormal embryos. * These embryos usually do not
continue to grow and no pregnancy is established. If an abnormal embryo does
result in a pregnancy, it is more likely to lead to an early miscarriage.
We can use hormonal testing to evaluate egg quality.* The first
of these tests are the FSH (Follicle Stimulating Hormone) and
Estradiol (an estrogen). These blood tests are performed on the second
or third day of the menstrual cycle ( the first day of flow is cycle day 1).
FSH is the hormone secreted by your pituitary gland to stimulate your
ovaries to produce estrogen. When the ovaries become resistant, FSH
levels rise in an increased attempt to stimulate the ovaries to function. An
FSH value above 10 mIU/ml is considered elevated and an Estradiol
value above 68 pg/ml is elevated.
What about me?
Although
statistics show that age is a factor in conceiving, remember that you
are an individual and you are the only statistic that counts. Statistics
provide probable outcomes, not absolutes, and there are always exceptions.
Fertility decreases over time and varies from one person to another. An
evaluation helps determine where you are in that life process.
If
fertility treatment is unsuccessful based on a diagnosis of diminished ovarian
reserve, options include egg donation, adoption, or choosing to live childfree.
While these decisions may be difficult, it is comforting to know that there are
options available, as well as support to assist you in achieving your goal of
building a family.
Table
1:| Age |
Pregnancy
Rates
Natural Cycle |
*Risk
all
Chromosomal
Abnormalities |
*Risk
Trisomy 21
(Downs Syndrome) |
Miscarriage
Rates |
|---|
| 25 | 25-30% | | 1:1000 | 10% | | 30 | 25-30% | 1:300 | 1:700 | 10% | | 35 | 18% | 1:134 | 1:300 | 25% | | 40 | 5% | 1:40 | 1:90 | 40% | | 45 | 1% | 1:11 | 1:22 | >50% |
Risk of chromosomal abnormalities at
mid-trimester (second trimester of pregnancy, around time of genetic
testing).
|  | Fertility Specialists of
Dallas
Phone: 214.750.5500
Presbyterian Hospital of
Dallas
8230 Walnut Hill Lane Suite 300
Dallas, TX 75231
Click here for
Directions
Presbyterian Hospital of Plano
6300 W.
Parker Rd
Bldg II, Suite 424
Plano, TX 75093
Click here for
Directions
Texarkana Satellite
1002 Texas Blvd Suite 401
Texarkana, TX 75503
903.793.5500
Click here for Directions |
|
