Fertility Chronicles is proud to present a special blog series, “From the Fertility Experts,” where leading fertility experts answer commonly asked questions for patients about their fertility health and treatment options. We hope this series can help patients navigate their personal fertility journeys.—Catherine T. Yang, Editor, Fertility Chronicles
Dr. David Barad, our guest blogger, shares his advice on ovarian reserve tests:
Before you undergo any laboratory testing, your age is probably the best single predictor of your reproductive success. If you are under age 38, you’re likely to have pretty good chances. If you are under age 32, I personally feel that laboratory testing should not be used to exclude you from any treatment.
That said, your doctor can provide several tests to tell how your ovaries are working and how their condition might affect your fertility treatment. They include the Day 3 FSH. antral follicle count, and anti-mullerian hormone tests. These tests aim to answer two basic questions: 1) Will you be able to produce eggs? 2) If so, will those eggs become healthy embryos? They are best seen as tests to see how your ovaries would function in the context of fertility treatment and not necessarily as a measure of your natural fertility. I will write about Day 3 FSH in this blog and then, explain antral follicles and anti-mullerian hormones in the next two blog posts, respectively.
Follicle Stimulating Hormone (FSH) is one of the first tests your doctor will use. FSH, a hormone secreted by your pituitary gland, tells your ovaries to grow mature follicles. If your ovaries are not responsive, FSH will rise until there is a response.
Imagine that your ovary is like a car trying to go up an icy hill. Increasing FSH levels is like stepping on the gas to go up that hill. Eventually you can make it to the top. An observer can judge how much traction your car has by how fast the tires are spinning. In the same way, your doctor can learn about your ovaries’ potential by seeing how much FSH it takes for you to have a normal cycle in which you ovulate.
As your ovarian follicles grow every month, they make estradiol (a type of estrogen), triggering your monthly reproductive cycle. Each day, your FSH level works in balance with your estradiol level, like two children on a see-saw. If your estradiol level is high, then your FSH level is likely to be low. If your estradiol is very low, your FSH will be at its highest.
For this reason your doctor will ask you to have your blood drawn on the second or third day of your menstrual cycle, when estradiol should be low. This is known as a baseline FSH, or a Day 3 FSH test. Your doctor will also check your estradiol to be sure that your FSH levels truly report how your ovaries are functioning. If estradiol is higher than 60 picograms per milliliter, your FSH might be artificially lowered and might falsely reassure you.
Once you measure your Day 3 FSH levels, what’s considered “normal”? FSH increases steadily as a woman ages. Therefore, there is a “normal” FSH level that is expected for every age group, called age-specific FSH. If you are 25 years old, your FSH should be less than seven, and if you are 40, an FSH of eight is in the normal range, for example. If your Day 3 FSH is higher than expected for your age, you might need more fertility medication during IVF treatment to see a response that is expected based on your age.
Some young women have a high baseline FSH, despite their age. For them, a high FSH doesn’t matter much unless it is over 15 to 20. For women under 32, an elevated FSH above 10 does not automatically mean that their chances are poor, and the best test of your ovarian reproductive function is to undergo an IVF treatment.