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    Here's How Birth Control Can Affect Your Biomarkers

    By Ashley Reaver, MS, RD, CSSD, December 21, 2021

    how birth control affects biomarkers

    We're often asked if hormonal contraceptives can affect female biomarkers. The answer? Yes. It makes sense then, that women begin to wonder how they are affected, and to what extent.

    Like any other medication, hormonal contraceptives (pills, patches, rings, IUDs, implants, and injections) interfere with the normal functioning of the body. Naturally, there can be some unintended residual effects. Therefore, some out-of-range biomarkers may be attributed to your contraceptive use, while others may be a combination of factors. It's important to note that throughout this blog post, we will refer to all hormonal contraceptives (pills, patches, rings, IUDs, implants, and injections), as OC – aka oral contraceptives. This may seem a misnomer, but in the current scientific literature, "OC" is used to characterize all hormonal contraceptives, unless indicated otherwise. We hope this post will help you better understand how your OC could be affecting some of your biomarker levels.

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    Low dehydroepiandrosterone-sulfate (DHEAS)

    DHEAS levels are significantly lower for OC users than non-OC users.1,2 DHEAS is a molecule that is synthesized into the sex hormones estradiol and testosterone, and is essential for energy, muscle and bone health, and sexual function for both men and women. The reduction in DHEAS by OC is potentially due to the suppression of androgens made by the adrenal glands, combined with higher cortisol production. DHEAS levels begin to drop soon after beginning OC and, depending on the duration of OC use, can take quite some time to increase once OC use is discontinued. DHEAS levels also naturally decline after the mid-20s.

    DHEAS over the lifespan

    Low testosterone

    Testosterone production is also suppressed while taking an OC, typically by up to 50%.2 Researchers propose this decrease is due to suppression of testosterone created in the ovaries, suppression of testosterone created in the adrenal glands, and increased SHBG levels. An important note here is how important testosterone is, not just for men – women also require testosterone for energy, muscle and bone health, and a healthy libido.


    Elevated sex hormone binding globulin (SHBG)

    SHBG can be elevated by up to 400% in OC users.2,3  SHBG binds to testosterone and reduces its bioavailability. Estrogens, like those found in OCs, result in a dose-related increase in SHBG production by the liver. Studies show that peak SHBG levels can be reached in as little as three weeks after beginning OC and, subsequently, can fall just as quickly after stopping use. Since increases in SHBG are dose-dependent, forms with lower dosages of estrogens, like IUDs, result in the lowest increase in SHBG. Conversely, forms with higher dosages (like the patch and the ring) result in the largest increases. Combined OC pills fall somewhere in the middle.

    Birth control and SHBG levels in women

    Elevated Cortisol

    OC users may have elevated cortisol levels due to the changes in the adrenal glands.2 Because the adrenal glands suppress the production of androgens while on OC, more cortisol may be made to siphon off the products that would otherwise go towards making androgens, like testosterone. Females with elevated cortisol levels should also consider lifestyle changes such as increasing sleep, reducing stress, meditation, and ensuring adequate calorie intake. 

    Birth control's impact on cortisol levels

    Elevated hsCRP

    Elevated hsCRP levels are also associated with OC use.4 Low-grade inflammation as a result of OC use may predispose individuals to a higher inflammatory response to physical activity, especially in athletes.A concerted effort to combat inflammation with a diet high in antioxidants like vitamins A, C, and E, as well as ample healthy fats and adequate sleep, can help to mitigate the damage of inflammation.

    Birth control's impact on inflammation

    Low folate

    A large meta-analysis found that OC users had significantly lower blood folate levels than non-OC users.6 The exact mechanism that impacts folate metabolism is unknown; however, the type of OC used, duration of OC use, baseline folate level, and nutrition status may exacerbate the reduction in blood levels.

    Folate is a critical nutrient during the first month of pregnancy, when many women may not even be aware that they are pregnant. Coupled with the impact of birth control, blood folate is at its lowest level during a female’s reproductive years. Since half of all pregnancies are unplanned, if you are taking birth control, talk with your doctor about supplementing with folate.


    Low vitamin B12

    OC use is associated with lower serum B12 concentrations, even when controlling for intake through diet.7,8 Similar to folate, researchers aren’t clear on whether OC results in a disruption of B12 absorption, recycling, or storage. B12 is another critical vitamin due to its role in DNA and red blood cell synthesis, as well as lipid and carbohydrate metabolism, and brain and nervous system function. B12 levels fluctuate throughout the female lifespan, but it is particularly critical for females during their reproductive years. OC users may present with low levels of blood B12 but be asymptomatic. For this reason, if you have lower vitamin B12 and you are taking oral contraceptives, focus on increasing your intake on vitamin B12 rich foods like meat, eggs, and dairy, and monitor your levels.

    B12 levels change throughout a woman's lifespan

    Higher ferritin

    One positive effect on the biomarker front is higher levels of ferritin in OC users.9 The higher levels of ferritin may be due to several factors,  including reduced menstrual bleeding frequency and amount, as well as inflammatory-driven elevations in ferritin.  

    Are you curious how your birth control is affecting your biomarkers? InsideTracker can help you identify and monitor any effects that your birth control may be having on your biomarkers. When reviewing your results, keep in mind that values outside of the optimal or normal zones may be expected based on your OC use. Your results can also be the start to a great conversation with your OB/GYN.


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    Ashley Reaver, MS, RD, CSSD
    Ashley is the Lead Nutrition Scientist at InsideTracker. As a registered dietitian and educator, Ashley enjoys cooking and teaching individuals the power that food has on their health. You’ll find Ashley hiking, eating, and spending time with her family. Follow her on Instagram @lower.cholesterol.nutrition.



    [1] 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.
    [2] 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.
    [3] 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.
    [4] Sørensen, Cecilie J., et al. "Combined oral contraception and obesity are strong predictors of low-grade inflammation in healthy individuals: results from the Danish Blood Donor Study (DBDS)." PloS one9.2 (2014): e88196.
    [5] Cauci, Sabina, Maria Pia Francescato, and Francesco Curcio. "Combined oral contraceptives increase high-sensitivity C-reactive protein but not haptoglobin in female athletes." Sports Medicine47.1 (2017): 175-185.
    [6] Shere, Mahvash, et al. "Association between use of oral contraceptives and folate status: a systematic review and meta-analysis." Journal of Obstetrics and Gynaecology Canada37.5 (2015): 430-438.
    [7] McArthur, Jennifer O., et al. "Biological variability and impact of oral contraceptives on vitamins B6, B12 and folate status in women of reproductive age." Nutrients5.9 (2013): 3634-3645.
    [8] Berenson, Abbey B., and Mahbubur Rahman. "Effect of hormonal contraceptives on vitamin B12 level and the association of the latter with bone mineral density." Contraception86.5 (2012): 481-487.
    [9] Sim, Marc, et al. "Iron regulation in athletes: exploring the menstrual cycle and effects of different exercise modalities on hepcidin production." International journal of sport nutrition and exercise metabolism24.2 (2014): 177-187.


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