Ovarian reserve refers to the reproductive potential left within a woman’s two ovaries based on number of eggs (oocytes). If you have diminished ovarian reserve, this means that the number of your eggs is lower than expected for your age. Although the relative quality (chromosomal normalcy or competency) of eggs in DOR patients may also be compromised, we often see quality being more aligned with a patient’s age rather than her number of eggs.
Normal aging causes most cases of diminished ovarian reserve, but genetic defects (Fragile X), X chromosome deletions, cancer treatments that collaterally damage oocytes (chemotherapy or radiation), ovarian surgery (usually to remove cysts associated with endometriosis), and cigarette smoking can cause DOR as well. In many cases there is no apparent direct cause for the relative decrease in ovarian reserve, but an autoimmune etiology is suspected as often these cases are associated with autoimmune diseases such as Hashimoto’s thyroiditis or autoimmune adrenal failure.
According to the American College of Obstetricians and Gynecologists, these are the average number of eggs you have at each age:
- 20 weeks of gestation: 6 to 7 million oocytes
- birth: 1 to 2 million oocytes
- puberty: 300,000 to 500,000 oocytes
- around age 37: roughly 25,000 oocytes
- around age 51, the average age of menopause in the United States: roughly 1,000 oocytes
Fertility doctors use all this information to determine whether a woman’s ovaries are “acting their age.” This information is critical to becoming pregnant and planning for either fertility treatment or fertility preservation. It is important to remember that even though women may have oocytes present in their ovaries until they hit menopause, the 5 to 10 years preceding menopause are characterized by subfertility in which fertility treatments are often required to overcome their issues.
There are several non-invasive tests you can have to determine your ovarian reserve. While there’s no way to reverse diminished ovarian reserve, there are many fertility treatment options your doctor can offer you.
Most Commonly Used Ovarian Reserve Testing Options:
- Day 3 FSH: The pituitary is the area of the brain that produces follicle stimulating hormone (FSH). When ovarian function starts declining FSH values increase in an attempt to stimulate the ovary to mature eggs. Normal FSH values are well below 10. If yours is above 9 on cycle day 2 or 3, it may indicate a decline in your ovarian reserve.
- Resting (Antral) Follicle Count: A transvaginal ultrasound is performed to count the number of resting/unstimulated ovarian follicles at the start of your period. It’s important to know what’s going on with your follicles as fertility medications may be less effective for those with a low number of resting follicles.
- Antimullerian Hormone (AMH): AMH is a hormone produced by the early eggs, so the higher the AMH level, the more eggs that remain in the ovary.
Should you get your ovarian reserve tested? The answer is a resounding YES for anyone who is having trouble getting pregnant. Moreover, I recommend ovarian reserve testing in young women annually, even if they are not interested at that time in conceiving, simply because we now have the ability to reliably freeze oocytes to preserve future fertility to a very significant extent. Should you see signs of a prematurely diminishing egg reserve, the egg freezing option is certainly worth considering and a consult with a fertility specialist to get the details may prove valuable.