Uterine fibroids and polycystic ovary syndrome (PCOS) are two common reproductive health concerns for women. Both are hormone-related diseases that can affect the menstrual cycle, incite pelvic pain, and affect fertility. But beyond a few common symptoms and complications, are these two conditions linked?
A landmark study found that among African American women, the incidence of fibroids was 65% higher among those who have PCOS compared to women without PCOS.1
What Are Fibroids?
Uterine fibroids are the most common tumors within the female reproductive system and grow within the muscle tissue of the uterus. About 20% to 80% of women develop fibroids by the time they reach age 50.2 Fibroids are non-cancerous and may cause no symptoms at all, but for many women they bring about severe symptoms like heavy periods, pelvic pain or pressure, and frequent urination.
The cause of fibroids is still unknown, but research suggests that genetics, hormonal imbalance (particularly estrogen and progesterone), and naturally occurring substances in the body called growth factors may play a role in fibroid growth.3
Some risk factors for fibroids include heredity, onset of menstruation at an early age, obesity, vitamin D deficiency, use of birth control, alcohol consumption, and a diet high in red meat and low in green vegetables.3 Race also plays a role, as black women have been found more likely to have fibroids than other racial groups, develop fibroids at a younger age, and to have more or larger fibroids.3
What Is PCOS?
Both women and men produce male hormones called androgens, but when a woman has PCOS, she produces more than normal. This occurrence along with an imbalance of female hormones, such as luteinizing hormone (LH) and follicle stimulating hormone (FSH), make it difficult for the ovaries to develop and release an egg each month, as seen during the ovulation phase of a healthy menstrual cycle. This leads to multiple cysts, or fluid-filled sacs, that develop on the ovaries.
Between 5% and 10% of women of childbearing age have PCOS.4 PCOS symptoms include an irregular menstrual cycle, acne, excess facial hair, male-pattern baldness, and weight gain.
The cause of PCOS isn’t clear, but factors include heredity, inflammation, and elevated levels of male hormones as well as high levels of insulin—a hormone that regulates how the food you eat is changed into energy and used by your body.5 Obesity may worsen PCOS symptoms.5
Fibroids and PCOS: What the Research Says
To investigate the possible connection between fibroids and PCOS, researchers at Boston University Slone Epidemiology Center examined findings collected from a large ongoing study that took place in 1995 called the Black Women’s Health Study.1 Within a 6-year period, over 23,000 African American premenopausal women with no history of fibroids were followed. To track participants’ health status, women were asked to complete mailed questionnaires every 2 years.
During this follow up, 3,631 new cases of fibroids were confirmed and reported.1 The researchers found that the incidence of fibroids was 65% higher among women with PCOS than women without PCOS.
What’s the Connection?
Given these results, the researchers concluded that PCOS was associated with an increased risk of fibroids, at least among African American women. But why?
Although we don’t know for sure, the researchers had a few theories. One possibility is that women with PCOS commonly have high levels of LH—a hormone that stimulates ovulation.1 LH may not only affect the ovaries but also directly influence the uterus and at high levels is associated with an increased risk of fibroids.1,6 What’s more, because LH levels are constantly elevated, ovulation often doesn’t happen.7
That being said, irregular ovulation is a hallmark of PCOS, and the researchers note that this also might influence the risk of fibroids.1 When the ovaries don’t release an egg during the menstrual cycle, they explain, estrogen continues to be released in the body without being balanced by progesterone. This imbalance may encourage the development and growth of fibroids.1
It’s important to note that although some research, as mentioned in this article, found a link between fibroids and PCOS, other research hasn’t found such a connection.8 For this reason, more research needs to be dedicated to this topic. However, if you’re experiencing any of the aforementioned symptoms, it’s important to educate yourself on both conditions and talk to your doctor about your medical history, risks and complications involved, and the possible treatments available.
1. Wise, L. A., Palmer, J. R., Stewart, E. A., et al. (2007). Polycystic ovary syndrome and risk of uterine leiomyomata. Fertil Steril, May;87(5):1108-1115.
2. U.S. Department of Health and Human Services Office on Women’s Health. (2018, Mar 16). Uterine fibroids. Retrieved from https://www.womenshealth.gov/a-z-topics/uterine-fibroids
3. Mayo Clinic. (2018, Mar 06). Uterine fibroids. Retrieved from https://www.mayoclinic.org/diseases-conditions/uterine-fibroids/symptoms-causes/syc-20354288
4. U.S. Department of Health and Human Services Office on Women’s Health. (2018, May 22). Polycystic ovary syndrome. Retrieved from https://www.womenshealth.gov/a-z-topics/polycystic-ovary-syndrome
5. Mayo Clinic. (2017, Aug 29. Polycystic ovary syndrome (PCOS). Retrieved from https://www.mayoclinic.org/diseases-conditions/pcos/symptoms-causes/syc-20353439
6. Baird, D. D., Kesner, J. S., & Dunson, D. B. (2006). Luteinizing hormone in premenopausal women may stimulate uterine leiomyomata development. J Soc Gynecol Investig, Feb;13(2):130-135.
7. Center for Young Women’s Health. (2016, May 25). PCOS (polycystic ovary syndrome): General information. Retrieved from https://youngwomenshealth.org/2014/02/25/polycystic-ovary-syndrome/
8. Abdel-Gadir, A., Oyawoye, O. O., & Chander, B. P. (2009). Coexistence of polycystic ovaries and uterine fibroids and their combined effect on the uterineartery blood flow in relation to age and parity. J Reprod Med, Jun;54(6):347-352.