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Most infertility specialists define an older woman as one who is more than 35 years, but this is an arbitrary number. A woman's fertility does not fall off at a particular age, but starts declining gradually after the age of 30. After 35, the drop is fairly dramatic; and after 38, it's even more so. However, there is no magic number at which fertility disappears and this decline is a progressive irreversible process.
In the past, it was assumed that as the woman got older, her entire reproductive system started failing. However, today we know that the uterus and the fallopian tubes remain relatively unaffected by age; and that the reason for the decline in fertility is the diminished number of eggs left in the ovary. Every girl is born with a finite number of eggs, and their number progressively declines with age. A measure of the remaining number of eggs in the ovary is called the "ovarian reserve"; and as the woman ages, her ovarian reserve gets depleted. The infertility specialist is really not interested in the woman's calendar (or chronological age), but rather her biological age - or how many eggs are left in her ovaries.
Various tests have been described, to measure the ovarian reserve, so that we can determine which patients are good candidates for treatment. These tests are based on measuring the FSH level in the blood; and include a basal (day 3) FSH level. A high level suggests poor ovarian reserve; and a very high level is diagnostic of ovarian failure. A test that can provide earlier evidence of declining ovarian function is the clomiphene citrate challenge test (CCCT).
This is similar to a "stress test" of the ovary; and involves measuring a basal Day 3 FSH level; and a Day 10 FSH level, after administering 100 mg of clomiphene citrate from Day 5 to Day 9. If the sum of the FSH levels is more than 25, then this suggests poor ovarian function, and predicts that the woman is likely to have a poor ovarian response (she will most probably grow few eggs, of poor quality) when superovulated. Another test which has been recently developed is the measurement of the level of the hormone, inhibin B, in the blood. Low levels of inhibin B (which are produced by "good" follicles) suggest a poor ovarian reserve. However, just because a test result is normal does not mean that the quality or number of the eggs produced will be good - the final proof of the pudding is always in the eating!
© Dr. Aniruddha Malpani and Dr. Anjali Malpani www.drmalpani.com
Credits: How to Have a Baby: Overcoming Infertility
