Ovarian reserve testing is currently the best way women can learn about their egg quality and fertility potential, but it is not perfect. The testing involves blood work for hormone levels that fertility specialists have used for years to counsel women about fertility but a recent study published in the Journal of the American Medical Association from the University of North Carolina shows these tests do not predict fertility as well as we previously thought.
What is ovarian reserve testing?
The blood tests are follicle stimulating hormone (FSH), estradiol, and antimullerian hormone (AMH). FSH (a gonadotropin hormone from the pituitary gland) and estradiol (an estrogen made by the ovaries) are done early in the menstrual cycle (usually cycle day 3) and studies have shown that a high FSH (usually >10mIU/mL) can predict poor quality, decreased success with IVF treatment, and higher risk of miscarriage from chromosomal abnormalities.
Quick fact: an estradiol always needs to be checked with FSH because a high estradiol level can falsely lower the FSH level, and a common mistake is to be falsely reassured by a low FSH if no estradiol is checked on the same day.
FSH and estradiol levels have been used by fertility specialists for decades to diagnose diminished ovarian reserve but levels fluctuate cycle to cycle and most fertility specialists will have stories of women with sky high FSH levels that conceived despite the odds.
Quick fact: A common misconception is that an FSH > 20 mIU/mL means someone is in menopause which is not necessarily true. Menopause is a clinical diagnosis of no menses (no periods) for over 6 months when the egg supply has run out. If someone has a very high FSH but they are still having menstrual cycles – they have diminished ovarian reserve but are not in menopause.
Anitmullerian hormone (AMH) is a hormone found in supporting cells around eggs. The higher the AMH level, the more supporting cells, and likely the higher the egg supply or ovarian reserve. AMH has only recently been adopted as a routine fertility test and fertility specialists are still trying to figure out how to interpret results, but in general AMH decreases with age and studies have shown that a low AMH (usually <1.0 ng/mL) can predict poor quality, decreased success with IVF treatment, and higher risk of miscarriage from chromosomal abnormalities.
What did the study show?
The recently published study evaluated 750 women who had been trying to conceive for 3 months or less (so not infertile which is defined as trying for 12+ cycles without conception). The women were evaluated for AMH, FSH, and estradiol and another less common test for ovarian reserve called inhibin B and followed for up to 12 months. Women with diminished ovarian reserve (defined as AMH < 0.7 ng/mL or FSH > 10 mIU/mL in the study) had similar chances of conceiving compared to the women with normal ovarian reserve testing over the year observed. The researchers accounted for issues that impact fertility such as age, smoking, and obesity which make the results more meaningful. No study is perfect and there are issues like the population studied was 77% Caucasian so may not represent all women and every lab uses different assays for hormone tests and values may not represent all results. However, these are interesting results and should be noted.
Is this new information?
No, there are previous studies that show limited interpretation of ovarian reserve tests. This study is larger than most and conducted in an interesting way difficult to do with lots of patients (following women over a 12-month period and observing outcomes without intervention).
Why is this important?
It is important because there is a push in the public and on social media for women to ‘Get their levels checked.’ Women should be informed of their ovarian reserve and look for problems early (before they are ready to start trying for their family). There is buzz around companies selling at-home hormone tests for women and more.
Knowledge and education are powerful and women should be able to check their hormone levels but in context. Women need to know that ovarian reserve testing is not perfect and if they get these levels checked they need to interpret the results with caution. Women with ‘normal’ levels can have fertility issues and women with ‘bad’ levels can still conceive naturally.
Do not let ovarian reserve define you. They may predict a fertility issue and poor results should not be ignored but they are not perfect and women should interpret with caution!
Dr. Shahine is a reproductive endocrinologist at Pacific NW Fertility in Seattle, WA.