Medically reviewed on March 8, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
Incredibly, the human reproductive journey starts well before we arrive into the world as babies. In fact, developing female fetuses harbor some 6 million oocytes (human eggs) in their ovaries while still in the womb. By the time a female fetus enters the world as a tiny human, between 500,000 and 1,000,000 of those 6 million eggs are still available [1].
Ovarian reserve testing (ORT) is a method to assess the number of eggs available in the ovaries—the “ovarian reserve”—and whether that quantity is appropriate for one’s age.
As a safe means of gauging one’s ability to conceive, ORT may offer meaningful insights into your reproductive health and overall well-being. In this article, we’ll take a closer look at how ovarian reserve testing works and what it can tell you about fertility.
People assigned female at birth are born with a finite store of eggs in their ovaries. This store diminishes over time, accelerating in momentum with age [2]. Estimating the number of remaining oocytes is one of the primary metrics used to assess female fertility.
While commonly used to estimate the number of eggs in the ovaries, certain kinds of ovarian reserve testing may also tell you the following:
There are two methods used in ovarian reserve testing:
Where in the reproductive cycle is measuring hormones important? There’s a delicate interplay of information between the brain and hormones that affects a host of actions in the monthly and lifelong reproductive cycle. These actions include:
By painting a more complete picture of various hormone levels, ORT can offer invaluable information about fertility potential and possible solutions for fertility treatment in those looking to start a family.
Below, we’ll take a look at three key hormones measured in biochemical ovarian reserve tests: follicle-stimulating hormone, estradiol, and anti-Müllerian hormone.
FSH is one of the most commonly tested hormones in ORT. Levels are measured during the early follicular phase of the menstrual cycle, typically around day 3. This is the time in which FSH is disbursed by the pituitary gland to start the growth of eggs within the ovary, launching the maturation process that precedes ovulation.
In normal reproductive cycles, FSH is stalled on two occasions, by two other key hormones:
Because FSH levels must decrease to allow for an egg’s release from the ovaries, heightened FSH levels may indicate:
In general, the higher the FSH levels are during this part of the cycle, the fewer eggs there are [3]. This is because as the ovarian reserve is depleted, less estradiol (the most prevalent type of estrogen) is produced, which in turn allows FSH to flow unchecked.
The American Journal of Obstetrics and Gynecology recommends the pairing of FSH level tests with an estradiol measurement to ensure an accurate reading.
Estradiol and FSH are in close communication during the follicular phase of the menstrual cycle. In some cases, when ovarian reserves are diminished, the ovaries produce an excessive amount of estradiol to bring FSH levels back down to a normal range. If FSH is tested in isolation, these levels may appear normal—even if the ovaries are in overdrive emitting estradiol trying to level them off [2].
By testing for both an FSH and estradiol inflation, ovarian reserve tests can get a more accurate reading of the relationship between these important hormones to determine whether the individual is at risk of DOR.
Anti-Müllerian hormone (AMH), also known as Müllerian-inhibiting hormone (MIH), is produced in the ovaries as egg follicles mature. Because of its relative stability in comparison to FSH and estradiol, AMH is a clinically important hormone in interpreting the health of an individual’s ovarian reserve [8].
AMH can indicate:
AMH testing has an excellent ability to ascertain where you are in the reproductive cycle. However, it’s not recognized as a reliable metric for gauging pregnancy outcomes in fertile people with uteruses or individuals pursuing pregnancy through assisted reproductive technologies such as IVF [3].
Although ovarian reserve tests can give you an assessment of the number of eggs remaining in the ovaries, they cannot determine the quality of the eggs available [2].
Age is the best indicator of the quality of eggs [3]. As your age increases, there is a higher likelihood of:
But if you're wondering about egg quality and quantity, like how many eggs a woman has, this can vary depending on age. In general, the condition of a person’s eggs correlates with the following aging patterns:
20s – In their 20s, people assigned female at birth have the best quality of eggs in their lifetime. The rate of chromosomal abnormality is low, around 30% on average.
30s – By their 30s, around half of an individual’s eggs are considered competent. At 35, people with uteruses are clinically considered of an advanced maternal age (AMA).
40s – People with female reproductive organs who are in their 40s and older have the highest incidence of aneuploidy. In fact, if over age 44, approximately 90% of eggs are at risk for chromosomal abnormalities [9].
Understandably, it can be difficult to digest the biological reality of fertility and outcome statistics among people at a more mature stage of their reproductive development.
An option that can help is egg freezing. Freezing your eggs means creating an egg reserve for later use. This can make a tremendous impact if egg quantity decreases, as there are fewer viable eggs as you get older.
Even so, there are many potential ways to pursue a path towards parenthood with positive health outcomes for both you and your future family. Hormonal therapy, assisted reproductive technologies, and diagnostic tools like ORT are all promising ways of taking ownership of your current reproductive health and your future family planning.
What ovarian reserve testing can (and can’t) tell you about your health Ovarian reserve testing is usually the first measure of assessing an individual’s fertility. It’s also an advantageous method for determining whether fertility treatment may help an individual or a couple get pregnant. Ovarian reserve tests may tell you:
With ORT, you can come to a clearer understanding of where you are in the reproductive journey so you can make an educated, coherent decision about family planning in your own time [10].
By measuring your FSH levels, our at-home Women's Fertility Test can provide information related to reproductive health. Also consider the at-home Women's Health Test, which lets you check in on 10 key hormones that help determine a woman's overall well-being.
How many eggs does a woman have?
Freezing your eggs: is it right for you?
Can ovarian cysts cause infertility?
References
1. Silber S. Unifying theory of adult resting follicle recruitment and fetal oocyte arrest. Reprod Biomed Online. 2015 Oct;31(4):472-5. Epub 2015 Jul 15. PMID: 26276043.
2. Ovarian reserve testing: a user’s guide. American Journal of Obstetrics & Gynecology. URL. Accessed March 8, 2022.
3. Ulrich ND, Marsh EE. Ovarian Reserve Testing: A Review of the Options, Their Applications, and Their Limitations. Clin Obstet Gynecol. 2019;62(2):228-237.
4. What causes amenorrhea? National Institutes of Health. URL. Accessed March 8, 2022.
5. Ovarian Reserve Testing. Endotext [Internet]. URL. Accessed March 8, 2022.
6. Shuster LT, Rhodes DJ, Gostout BS, Grossardt BR, Rocca WA. Premature menopause or early menopause: long-term health consequences. Maturitas. 2010;65(2):161-166.
7. The Normal Menstrual Cycle and the Control of Ovulation. Endotext [Internet]. URL. Accessed March 8, 2022.
8. Zec I, Tislaric-Medenjak D, Megla ZB, Kucak I. Anti-Müllerian hormone: a unique biochemical marker of gonadal development and fertility in humans. Biochem Med (Zagreb). 2011;21(3):219-30. PMID: 22420235.
9. Cimadomo D, Fabozzi G, Vaiarelli A, Ubaldi N, Ubaldi FM, Rienzi L. Impact of Maternal Age on Oocyte and Embryo Competence. Front Endocrinol (Lausanne). 2018;9:327. Published 2018 Jun 29.
10. Jirge PR. Ovarian reserve tests. J Hum Reprod Sci. 2011;4(3):108-113. doi:10.4103/0974-1208.92283