More than 15% of couples in this country have difficulty conceiving a child. Delayed childbearing has resulted in more women in their late 30s and early 40s attempting conception than ever before. In fact, 20% of women in the United States now have their first child after age 35.
Some women seeking to conceive after age 40 have no difficulty in achieving a pregnancy. For those who do, however, prompt and thorough evaluation and aggressive treatment are crucial. The probability of having a baby decreases 3-5 % per year after the age of 30, and at a faster rate after 40. Unfortunately, as women age they also have a higher chance of miscarrying.
At birth, a woman has all the eggs she will ever have. As an egg ages, it is more likely to develop a chromosomal abnormality. A fertilized egg with abnormal chromosomes is the single most common cause of miscarriage: at least half of all miscarriages are due to abnormal chromosomes. A woman in her 20s has only a 12-15% chance of having a miscarriage each time she becomes pregnant. On the other hand, a woman in her 40s faces a 50% risk of miscarriage.
Trying to conceive for one year before an infertility evaluation may not be appropriate in women over 40. If a woman is over 40 and the couple has been trying to conceive for over six months, a basic infertility evaluation is indicated.
A basic infertility evaluation includes a history focused on fertility factors, physical examination, and laboratory evaluation. The evaluation should determine if the partner can produce normal semen, if the fallopian tubes are open, and if the ovaries are able to produce eggs that are likely to establish a pregnancy. The three most important laboratory evaluations are a semen analysis, baseline (day 3) FSH to determine the "ovarian reserve," and a hysterosalpingogram (HSG) to insure that the tubes are open.
For a woman over 40, your doctor should perform the basic evaluation over a period of one to two months. You and your health care provider together should make every attempt to correct any problem that is uncovered in the basic evaluation. Aggressive therapy may be indicated, because time is the biggest factor.
The pituitary gland produces Follicle Stimulating Hormone (FSH), which is responsible for the cyclic development of eggs every month. As a woman's eggs become less capable of producing a pregnancy, the levels of FSH begin to rise. Women who have gone through menopause have very high levels of FSH (and are incapable of becoming pregnant with their own eggs). Young women who have had an accelerated decline in the quality of their eggs can also have high FSH levels.
Findings associated with age-related decline in fertility may include changes in FSH levels, recent cycle shortening or irregularity, climacteric symptoms, and low numbers of follicles in response to stimulation. Previous ovarian surgery with removal of an ovarian cyst or partial removal of ovarian tissue might lead to earlier loss of ovarian function. Your doctor will estimate your "ovarian reserve" by testing your cycle day 3 Follicle Stimulating Hormone (FSH). Normal levels for FSH on day 3 are different for different laboratories. In many laboratories, the normal level is less than 10 IU. Women with FSH levels slightly above normal are considered borderline, and women with FSH levels that are consistently elevated have an extremely low chance of conceiving and carrying to term. To be valid, the FSH must be drawn in conjunction with an estradiol, and the estradiol should be less than 50 pg/ml.