Ovarian reserve is basically another phrase for the biologic clock.
Younger women generally have more eggs and more of those eggs are normal, compared to older women. Women who have gone through menopause generally have no normal eggs remaining and they cease to ovulate. Between normal ovarian function and menopause, there is a state called diminished ovarian reserve.
Women are born with 1 – 2 million eggs and every day of a woman’s life she is losing eggs. Some women are born with fewer eggs, some women lose them more quickly, and some women accumulate damage in their eggs more rapidly than others and they develop diminished ovarian reserve.
Women with diminished ovarian reserve frequently have a more difficult time getting pregnant.
Genetic predisposition is one cause of diminished ovarian reserve, so premature menopause in a relative should alert women to the possibility that this can occur in them. Other causes include smoking, ovarian surgery (such as the removal of a cyst).
A sign that ovarian reserve can be decreasing is if a woman's menstrual cycle begins to shorten betweeen periods. If a woman has always menstruated every 28-30 days and starts to menstruate every 24-26 days, this can be a sign of diminished ovarian reserve and should be evaluated.
Now women have the choice of testing ovarian reserve through their physician, or in the privacy of their own home through urine test kits that are used much like a home pregnancy test.
The kits range in price from under $4 to nearly $100, and they test for a hormone called follicle stimulating hormone (FSH) on or around menstrual cycle day 3. FSH is what makes eggs grow. It’s like the gas pedal to the ovary. Like a well tuned car does not require someone to mash hard on the gas pedal to get up to speed, the normal ovary only requires a little FSH to ovulate. If the FSH is high, then the ovary is not working well and the woman has diminished ovarian reserve.
The inexpensive kit costs around $4 per test and is available at http://www.early-pregnancy-tests.com/fsh-tests.html . This kit detects the equivalent of an FSH of 25 mIU/ml, which is consistent with infertility and possible menopause. A normal test is when the FSH is below 25 mIU/ml. The problem is, women are generally infertile when FSH exceeds 17 mIU/ml.
A more sensitive kit by Genosis Ltd, called Fertell, can detect FSH levels of 10 mIU/ml, which is consistent with diminished ovarian reserve. Fertell has recently become unavailable in the United States, but may be purchased on line. A normal test is when the FSH is below 10 mIU/ml
The problem with both tests is that they only measure 1 hormone, FSH, which by itself can be meaningless. To know if the FSH is valid, an estrogen level must accompany it.
If a woman has a normal test it can be falsely normal (because estrogen is elevated prematurely – as can be seen in women with diminished ovarian reserve. See Pitfalls of Day 3 FSH Testing at: http://www.trmbaby.com/welcome/WebPearlsDec08FSH.pdf .
So a normal test does not mean the woman has normal ovarian reserve.
An abnormal test can be falsely abnormal, too. During the midcycle, many women will bleed due to a temporary drop in estrogen associated with ovulation. If the woman thinks this is her period, she might measure FSH at an inappropriate time. If a woman measures her FSH during the midcycle, the FSH is normally high and might trigger a positive test.
So either way, these tests need to be confirmed by a doctor. This is the best way to avoid false alarms and false reassurances.