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The Best Predictors of Your Fertility
June 29, 2013
When considering a fertility evaluation, most women take to the internet to understand the various fertility tests to be conducted and what the test results mean. While some tests are more accurate than others, each of these tests serves as a piece of the fertility puzzle; the two biggest pieces of that puzzle being age and length of time having unprotected sex.
Once a woman reaches the age of 35, her fertility falls more rapidly than it had on its steady decline from birth until her mid-thirties. A woman under the age of 35 is recommended to seek a fertility evaluation after one year of trying to conceive, while a woman over the age of 35 should do so after just six months. There are precious few years after the age of 35 within which a fertility doctor can treat a patient, so time is of the essence.
Aside from age and time spent trying to conceive a doctor can see the bigger picture of a woman’s fertility via lab tests, including:
- Day Three Follicle Stimulating Hormone (FSH)
- Estradiol, which at abnormal levels can interfere with FSH and give a false impression of fertility
- Anti Mullerian Hormone (AMH)
- Antral Follicle Count (AFC), which is the number of small follicles between 2-8mm visible by ultrasound in a woman’s ovaries
Ricardo Yazigi, M.D. of Shady Grove Fertility Center in Towson, Maryland says each of these tests yields a result that falls within a normal or abnormal range, but a woman’s age is the key to interpreting these results. “A test that comes back with an abnormal result has an entirely different meaning if the woman is young versus if she is older. We like for AFC to be above 10 but an AFC lower than 10 can have different meanings depending on the woman’s age. The same applies for AMH,” he explains.
Because it is difficult to standardize and interpret these test results, fertility doctors continue to use age as the primary factor in predicting how well a patient will respond to ovarian stimulation. “There is difficulty interpreting AMH levels because it is a fairly new test and not standardized. A normal AMH is anything over 1, and 0.9 is low-normal, but this is not an absolute measure. So we get together a bunch of tests, the woman’s age, and her history and look at all of the pieces. One test may be abnormal and the others normal. This is just an attempt to predict the outcome of the patient’s response to ovarian stimulation,” says Yazigi.
Fertility clinics, like Shady Grove, often use a formula for calculating the patient’s likelihood at IVF success which takes into consideration her age and fertility test scores. Typically, for a woman who is healthy, 31 years of age, and has a normal maximum FSH, AMH, and AFC, her predicted live birth rate is 58%. A woman 41 years of age with the same test scores will have a predicted success rate of just 18%. A 31 year old with an FSH of 14 comes down to 51% chance of live birth and a 41 year old with FSH of 14 comes down to 17% chance.
Dr. Yazigi advises: “Today, your fertility is not as good as it was yesterday, but it is much better than it will be tomorrow.”
Since age and time trying to conceive are the most important factors for predicting a woman’s fertility, women should understand that the inability to conceive after one year of unprotected intercourse (without using any method of tracking ovulation) is all the time and effort you need before seeking a fertility evaluation.