4 Key Blood Biomarkers Associated with Female Fertility

Explore the intricacies of female fertility markers to better understand the roles of testosterone, SHBG, cortisol, and DHEAS in female fertility. Uncover their impact on a woman's overall reproductive health.

Diana Licalzi
By Diana Licalzi
Lucia Gcingca
Edited by Lucia Gcingca

Published March 6, 2024.

A  man and a pregnant woman standing in a kitchen with a baby - 4 Key Blood Biomarkers Associated with Female Fertility

Female infertility can be confusing, discouraging, and all-around difficult to talk about. But if you're experiencing it, know that you're not alone.

The truth is female infertility is a common problem in the United States—roughly 10% of all women aged 15-44 experience difficulty getting pregnant or staying pregnant. [1] 

Some contributing factors, like age and conditions affecting the female reproductive system, are out of anyone's control. But, there are steps you can take to improve your fertility status, as certain lifestyle changes can improve critical blood biomarkers. [2]

» Uncover how birth control can affect your biomarkers

Female fertility markers: Blood work and key hormones

InsideTracker blood tests assess a handful of hormones linked to reproductive health. This article will explain how these biomarkers impact female fertility and point out possible causes of abnormal levels.

Please note that these biomarkers do not give a comprehensive picture of fertility, and there are numerous other markers associated with fertility that InsideTracker does not test.

*Consult your physician for a better understanding of your reproductive health.

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1. DHEAS and female fertility

DehydroepiandrosteroneDHEAS, a sex hormone, acts as a precursor for estrogen and testosterone. Estrogen plays a vital role in reproduction as it is needed for ovulation—the release of an egg from a woman’s ovaries. [3] And because DHEAS gets converted to estrogen, lower DHEAS can result in lower estrogen and difficulty getting pregnant. [3, 4]

Increased stress levels, over-exercise, and insufficient calories (especially fats) can lead to below-normal DHEAS levels. DHEA supplements are readily available in the United States, but InsideTracker does not recommend them due to their unreliable quality and unknown health risks.

Stress-reducing techniques, adequate nutrition, and regular exercise of moderate intensity can all help increase DHEAS levels. It is important to note that DHEAS in women naturally peaks in the mid-20s before slowly declining with age.

A  diagram of the female DHEAS life span - 4 Key Blood Biomarkers Associated with Female Fertility

On the contrary, overactive adrenal glands, polycystic ovary syndrome (PCOS), and early puberty can lead to high DHEAS levels. These conditions can result in difficulty controlling weight, menstrual irregularity, and infertility. [5]

2. Testosterone and female fertility

Testosterone plays an important role in reproductive health. Women need only small quantities of testosterone—too much or too little can interfere with fertility. [6] 

A recent study indicated that testosterone helps to promote the development of follicles—structures that hold and release eggs during ovulation. [7] Testosterone is also closely linked to normal libido and sex drive, indirectly affecting fertility.

As women age and enter menopause, their testosterone levels naturally decrease by as much as 15%.8 Similarly, birth control changes normal hormone balances in women; it can decrease testosterone by up to 50% and cause it to remain relatively low, even after birth control has stopped. [9,10]

A poster with the words Bio Markers 101 - Testosterone on it.

On the other hand, lifestyle factors, including elevations in blood pressure, LDL cholesterol, and total cholesterol, can all lead to increased testosterone levels. [11] Underlying medical issues like polycystic ovarian syndrome (PCOS) can also cause women to consistently produce too much testosterone in their ovaries.

If you have tested with InsideTracker and noticed elevated testosterone, it could also be due to your menstrual cycle. Testosterone levels spike around day 14 of normal menstrual cycles in premenopausal females. [12] Use an app like Period Tracker to track your cycle and test during a more optimal time. As with all other markers, speak to your doctor about high levels of testosterone.

» Curious about InsideTracker? We answer the question, what is InnerAge 2.0?

3. SHBG levels in females and fertility

Sex Hormone Binding Globulin, SHBG, is responsible for safely transporting sex hormones, mainly testosterone, throughout the bloodstream and regulating testosterone levels within the body. Since SHBG plays a big role in maintaining proper hormone function, our bodies need to have healthy levels of SHBG.

Multiple factors increase SHBG in the blood and decrease free testosterone. The aging process (particularly seen in postmenopausal women), pregnancy, and undernourishment all contribute to above-normal levels. [13] And as before, hormonal contraceptives can significantly influence levels of this biomarker—up to a 400% increase. [9,14]

a bar chart showing the percentage of SHBG in females - SHBG levels in females and fertility

Even after ceasing birth control, women may still have increased levels of SHBG in their bloodstream. [10] Proper nourishment and switching to non-hormonal contraceptives can help achieve normal SHBG levels. Similar to DHEAS, certain conditions like PCOS, Cushing's syndrome, and steroid use can result in low SHBG and, as a result, also contribute to elevated free testosterone. [6]

» Uncover what every woman should know about Sex Hormone Binding Globulin

4. Cortisol and female fertility

Cortisol, a steroid hormone produced by the adrenal glands, performs many vital functions in the body, including the regulation of energy, metabolism, and immunity.

The body also releases cortisol to activate our "flight-or-fight" responses to counteract acutely stressful situations. If cortisol levels stay elevated for extended periods, however, they can lead to chronic stress.

A screen shot of a website with food items on it - Cortisol and female fertility

This long-term activation of the stress-response system can interfere with the normal functioning of other body systems, including reproductive health. Several studies demonstrate a relationship between stress, cortisol, and infertility—higher levels of stress and cortisol result in a decreased fertility rate. [15]

Lifestyle strategies for women looking to balance cortisol levels

Inadequate calorie intake and strenuous physical activity can also contribute to elevated cortisol levels. [6] Women with elevated cortisol levels should consider lifestyle changes such as increasing sleep, engaging in stress-reduction techniques like meditation, and ensuring adequate calorie intake.

» Check out InsideTracker’s personalized insights for women’s health

How to measure female fertility markers and address concerns

An InsideTracker blood test can help you better understand the levels of these biomarkers that are optimal for you and your body. These biomarkers provide a glimpse into reproductive health but are not comprehensive measures.

*If you are concerned about abnormalities in your blood levels of any of these biomarkers, we recommend you speak to a doctor, particularly an endocrinologist.


[1] https://www.womenshealth.gov/a-z-topics/infertility

[2] https://www.hormone.org/~/media/Hormone/Files/Questions%20and%20Answers/Women/FS_MWH_Infertility_Women_EN%20612.pdf

[3] https://www.medicalnewstoday.com/articles/321064.php

[4] https://www.zrtlab.com/blog/archive/struggling-with-infertility-part-2-hormones-tested-in-the-zrt-fertility-profile

[5] https://www.mayocliniclabs.com/test-catalog/Clinical+and+Interpretive/113595

[6] https://labtestsonline.org/tests/sex-hormone-binding-globulin-shbg

[7] https://www.urmc.rochester.edu/news/story/4022/female-fertility-whats-testosterone-got-to-do-with-it.aspx

[8] Rannevik, G., et al. "A longitudinal study of the perimenopausal transition: altered profiles of steroid and pituitary hormones, SHBG and bone mineral density." Maturitas 21.2 (1995): 103-113.

[9] Zimmerman, Y., et al. "The effect of combined oral contraception on testosterone levels in healthy women: a systematic review and meta-analysis." Human reproduction update20.1 (2014): 76-105.

[10] https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1743-6109.2005.00198.x

[11] Kische, Hanna, et al. "Clinical correlates of sex hormones in women: The study of health in Pomerania." Metabolism 65.9 (2016): 1286-1296.National Academies Press.

[12] Murphy, Ana Alvarez, et al. "Effect of low-dose oral contraceptive on gonadotropins, androgens, and sex hormone binding globulin in nonhirsute women." Fertility and sterility 53.1 (1990): 35-39.

[13] https://www.mayocliniclabs.com/test-catalog/Clinical+and+Interpretive/9285

[14] Raps, M., et al. "Sex hormone‐binding globulin as a marker for the thrombotic risk of hormonal contraceptives." Journal of Thrombosis and Haemostasis10.6 (2012): 992-997. [15] Vitale, Salvatore Giovanni, et al. "The Impact of Lifestyle, Diet, and Psychological Stress on Female Fertility." Oman medical journal 32.5 (2017): 443.