Fibroid Basics
Knowledge is power, and it’s kryptonite for anxiety. If you’ve gotten a fibroid diagnosis and are feeling confused or worried, let’s dig in to the basics to help you understand what fibroids are, how they can affect your life, and what your options are.
Keep reading to learn:
What are uterine fibroids?
Uterine Fibroids are non-cancerous growths or tumors that develop in or on the uterus. Fibroids are the most common form of tumor found in women worldwide¹. More than 70% of us² will develop fibroids before we turn 50 years old.
Fibroids are made of muscle and fibrous tissue, and are also known as leiomyomas or myomas³. Fibroids are one of the most common reproductive health conditions among people assigned female at birth.
For some people, fibroids don’t cause any trouble—you might not even know they’re there. For other people, they cause a lot of trouble and can make your life pretty miserable. (Learn more about the problems fibroids cause.)
Although fibroids are not life-threatening, they can negatively impact your quality of life, especially if they lead to heavy periods, pain, fertility issues, or a variety of other problems.
1) https://pmc.ncbi.nlm.nih.gov/articles/PMC9277653/ - Comprehensive Review of Uterine Fibroids: Developmental Origin, Pathogenesis, and Treatment
2) https://pmc.ncbi.nlm.nih.gov/articles/PMC8432600/ - Uterine Fibroids: Assessing Unmet Needs from Bench to Bedside
3) https://www.mayoclinic.org/diseases-conditions/uterine-fibroids/symptoms-causes/syc-20354288 - Mayo Clinic, Uterine Fibroids Overview
Are uterine fibroids cancerous? Can uterine fibroids cause cancer?
No. For real. Fibroids are NOT cancer.¹ Breathe, sis. They are benign (noncancerous) tumors that develop from the smooth muscle tissue of the uterus.
Fibroids do not increase the risk of uterine cancer¹.
Fibroids are not cancerous.¹
Fibroids do not turn into cancer.¹
Fibroids will not increase your risk of getting other uterine cancers.¹
In very rare cases (less than 1 in 1,000), a cancerous tumor called a leiomyosarcoma² can develop in the uterus. However, this is unrelated to having fibroids.
Because fibroids and leiomyosarcomas can sometimes have similar symptoms, doctors may recommend imaging tests like an MRI or ultrasound, or even a biopsy, if there are concerns.
If a fibroid is growing rapidly, causing extreme pain, or behaving unusually, further evaluation may be necessary. But in most cases, fibroids are harmless and do not lead to cancer.
1) https://www.mayoclinic.org/diseases-conditions/uterine-fibroids/symptoms-causes/syc-20354288 - Mayo Clinic, Uterine Fibroids Overview
2) https://www.cancer.gov/pediatric-adult-rare-tumor/rare-tumors/rare-soft-tissue-tumors/leiomyosarcoma - NIH National Cancer Institute, Leiomyosarcoma
How are fibroids diagnosed?
Fibroids are usually diagnosed through a combination of medical history, physical examination, and imaging tests. If a person experiences heavy periods, pelvic pain, bloating, or fertility issues, a doctor may suspect fibroids and recommend further evaluation. This is why it’s crucial to talk to your doctor if you have these symptoms.
We’ve been trained to believe that periods are painful, and we’re supposed to just “deal with it” but if your periods are really heavy, super painful, your bloating is intense, and/or if you’re having fertility issues, get checked for fibroids. Seriously.
Common Diagnostic Methods:
Pelvic Exam¹: A doctor may feel for enlarged or irregularly shaped uterus, which can indicate fibroids. However, small fibroids may not be detectable this way.
Ultrasound¹: The most commonly used imaging test, transabdominal or transvaginal ultrasound uses sound waves to create images of the uterus and detect fibroids.
MRI (Magnetic Resonance Imaging)¹: Provides a detailed view of fibroids, including their size, number, and location. And MRI is used when planning fibroid treatment.
Hysterosonography (Saline Infusion Sonogram)¹: A specialized ultrasound that uses saline to expand the uterus, helping detect fibroids inside the uterine cavity.
Hysteroscopy¹: A thin scope with a tiny camera at the end is inserted through the cervical opening and into the uterus to examine fibroids up close, especially if they are inside the uterine lining.
Hysterosalpingography³. A dye is used to help the uterine cavity and fallopian tubes show up on X-rays. This test can help determine if your fallopian tubes are open or are blocked, and it can reveal some submucosal fibroids. Especially useful for fertility concerns.
CT Scan or X-ray¹: This is rarely used but may help in complex cases.
Getting a proper diagnosis is so important. Pay attention to your body. If you notice that your period is getting worse over time, talk to your doctor, and if they’re not taking you seriously, get a second opinion.
My diagnosis story: My periods were always painful but they kept getting heavier and more painful—like, “it’s so bad, I can’t leave the house.” My doctor dismissed my concerns, which was incredibly frustrating. After she told me to take an Advil (🙄 I’m not kidding) and I pushed back that I was far beyond the level of what #$%&ing Advil could manage, she agreed to do an initial ultrasound which found that I had two fibroids. My doctor said it was nothing to worry about, gaslighting me and blowing me off for a couple years. She proposed “watchful waiting” even though I was already having terrible symptoms.
But my body was like, “Nope. Girl, something is wrong.” I’d also been keeping track of my symptoms in a journal and it was right there in black-n-white that things were getting worse. So I got a second opinion. The second doctor took my pain and symptoms seriously—she referred me for an MRI, and guess what: turns out that I actually had more than two dozen fibroids! No wonder I was in horrible pain throughout my lower abdomen and lower back, intensely bloated/swollen, and my periods were a nightmare of constantly heavy flow, big clots, and excrutiating pain.
Getting my fibroids treated completely turned my life around. That required getting a proper diagnosis. Now my periods are super light, two days long, and almost entirely painless. Don’t ignore your body. Advocate for the care you deserve.
About “Watchful Waiting”²: After fibroids are diagnosed, your doctor might just suggest something called watchful waiting. This means that no action will be taken but you’ll have regular follow-ups to see if the fibroids grow, get worse, or cause problematic symptoms. This is only an appropriate course of action if you’re not having any fibroid symptoms. If you’re having symptoms, you deserve treatment. And this “watchful waiting” period isn’t a free pass to ignore the situation. It’s watchful. So get a journal and keep track of your fibroids symptoms and what your period is like. Write down what each day of your period is like—flow, pain, and other symptoms. Also write down the dates and severity level of other problematic fibroid symptoms, like frequent urination, constipation, upset digestion, bloating, and the severity, location, and frequency of other fibroid-related pain like lower back pain and abdominal bulk feelings.
If you have symptomatic fibroids, your doctor should discuss treatment options for you based on your fibroids’ sizes, symptoms, and your future fertility plans.
1) https://pubmed.ncbi.nlm.nih.gov/28084714/ - Uterine Fibroids: Diagnosis and Treatment
2) https://pubmed.ncbi.nlm.nih.gov/25365466/ - Contemporary management of uterine fibroids: focus on emerging medical treatments
3) https://www.mayoclinic.org/diseases-conditions/uterine-fibroids/diagnosis-treatment/drc-20354294 - Uterine fibroids, Diagnosis
What size are fibroids?
Uterine fibroids can vary in size¹, from as small as a seed to as large as a watermelon.
Fibroids are considered small if they’re less than 1 cm (centimeter) up to 5 cm (centimeters).²
Fibroids are considered medium if they’re between 5-10 cm.
Fibroids are considered large if they’re 10 cm or larger.
For reference:
A pea is about 1 cm
A peanut is about 2 cm
A grape is about 3 cm
A walnut is about 4 cm
A lime is about 5 cm
An egg is about 6 cm
A peach is about 7 cm
A grapefruit is about 10 cm
My fibroids: “I had over two dozen fibroids ranging in size from a pea up to the size of a lime. Because of this, my uterus was much bigger than normal. The doctor who solved my fibroid problems said that a regular uterus is about the size of a lemon. But because of my fibroids, my uterus was the size it would be if I were 3-4 months pregnant. No wonder my pants stopped fitting! I thought I was just gaining weight, but it turned out that my uterus was growing bigger because my fibroids were growing bigger. I constantly felt this heavy, bulky feeling in my lower belly, and I wasn’t imagining it. I was literally carrying around a fibroid “fruit bowl” in my belly. 🫠
1) https://pubmed.ncbi.nlm.nih.gov/28084714/ - Uterine Fibroids: Diagnosis and Treatment
2) https://www.usafibroidcenters.com/uterine-fibroids/fibroid-sizes/
Where do fibroids grow? What are the different types of fibroids?
Fibroids can grow inside the uterine wall, on the outer surface of the uterus, or within the uterine cavity. It’s possible to have only one kind, or multiple kinds of fibroids at the same time. (I had a variety pack.)
A lot of the time a single uterus will have multiple¹ fibroids. They can grow singly, or in clusters.
I’m gonna use a house 🏠 as a metaphor to help you visualize where these fibroids are.
Submucosal²: Inside the uterine cavity. This is the empty space of your uterus, like the interior rooms of your house. The fibroid isn’t just floating in space though, it’s attached to one of the walls of your uterus.
Intramural²: Within the muscular wall of the uterus. Think of this like the insulation in your home’s walls.
Subserosal²: On the outside of the uterus. Think of this like if your house randomly started growing extra porches around the outside.
Pedunculated²: Stalks that extend from the uterine wall. This would be like if a tree started growing straight out of the wall of your house, either inside or outside your house.
Uterine fibroids only show up in and around the uterus. When fibroids grow somewhere else in the body, they’re called fibromas³. These can grow almost anywhere including the skin, muscles, nerves, breasts, and even internal organs. But this website only focuses on uterine fibroids that affect the uterus.
1, 2) https://www.nichd.nih.gov/health/topics/factsheets/uterine - Uterine Fibroids
3) https://my.clevelandclinic.org/health/diseases/23991-fibroma - Cleveland Clinic, Fibroma
Why do fibroids grow? What causes fibroids to develop?
While the medical community can’t give one exact reason why fibroids grow, research suggests that it has something to do with our hormones, estrogen and progesterone¹ specifically. Especially estrogen. These hormones do a lot of great things for us, but sometimes they can also make bad shit happen too, like spurring fibroids to grow during our reproductive years when our hormone levels are ramped up.
These hormones stimulate the growth of the uterine lining during the menstrual cycle and can also promote fibroid growth. This is why fibroids often grow during reproductive years and shrink after menopause, when hormone levels drop. After menopause, when these hormones drop, fibroids often (but not always) will shrink.
Other factors that can affect whether you will get fibroids:
Genetics²: If the women in your family had fibroids, you’ll be more likely to.
Ethnicity²: Any ethnicity can get fibroids but African American women are more likely to.
Growth hormones¹: Proteins that influence tissue development
High blood pressure²: Proteins that influence tissue development
Inflammation³: If there’s more inflammation in the body, there’s a higher chance of you growing fibroids and experiencing fibroid pain
Obesity²: Being overweight can be associated with more risk of developing fibroids
Diet²: Eating lots of processed foods containing food additives², drinking lots of alcohol, eating lots of red meat, Vitamin D dificiency², high consumption of soy² which can mimic estrogen; deficiency of multiple micronutrients¹
Lifestyle: High stress¹, lack of exercise
Age²: 30s and 40s are more likely to develop fibroids
Childfree²: if you don’t birth any babies, you’re at a higher risk of getting fibroids.
Exposure to estrogen-mimicking chemicals⁴: These are found in plastics, personal care products, and processed foods
Fibroids don’t always behave the same way, even within the same body. Some fibroids remain small and stable, while other fibroids will grow larger over time.
1) https://www.nichd.nih.gov/health/topics/uterine/conditioninfo/causes - What causes uterine fibroids?
2) https://www.nichd.nih.gov/health/topics/uterine/conditioninfo/people-affected - What are the risk factors for uterine fibroids?
3) https://pmc.ncbi.nlm.nih.gov/articles/PMC9277653/ - Comprehensive Review of Uterine Fibroids: Developmental Origin, Pathogenesis, and Treatment
4) https://pmc.ncbi.nlm.nih.gov/articles/PMC8240765/ - The role of endocrine-disrupting chemicals in uterine fibroid pathogenesis
Who is most at risk for developing fibroids?
See the list above! Fibroids are more common in African Americans, but anyone with a uterus can get them. The combination of contributing factors can lead to a higher risk.
Several factors can increase the risk of developing fibroids, including¹:
Age: Fibroids tend to show up in the middle adulthood years, ages 30–50.
Family history: Having a mother or sister with fibroids increases the risk.
Race: Studies show that Black women are more likely to develop fibroids, often at younger ages and with more severe symptoms.
Stress: Anyone can experience chronic stress, which contributes to fibroids. This risk increases if you’re also experiencing structural racism, which may be a contributing factor in why Black women are the most likely group to develop fibroids².
Hormones: Estrogen and progesterone fuel fibroid growth, so high hormone levels (such as during pregnancy) can encourage their development.
Lifestyle factors: Obesity, eating lots of red meat and processed foods, alcohol consumption, and lack of exercise may increase risk.
Early menstruation: Starting periods at a younger age (before age 10) has been linked to a higher likelihood of fibroid development.
While these factors can increase the likelihood of developing fibroids, it’s not a crystal ball. Some people with these risk factors won’t get fibroids. Some people who live perfectly healthy lives without any of these risk factors might still develop fibroids. ¯\_(ツ)_/¯
But if you want to lower your chances of developing fibroids, and want to reduce fibroid symptoms, you can focus on managing your hormone levels, eating healthy, exercising, and getting regular OB/GYN checkups to monitor and potentially reduce the impact of fibroids.
1) https://pmc.ncbi.nlm.nih.gov/articles/PMC6247381/ - Burden, Prevalence, and Treatment of Uterine Fibroids: A Survey of U.S. Women
2) https://www.nichd.nih.gov/newsroom/news/032824-microRNA-uterine-fibroids - Science Update: Stress, microRNA linked to uterine fibroids, preliminary NIH-funded study suggests
How common are fibroids?
Fibroids are very common, especially in people assigned female at birth. Fibroids are most likely to be discovered, or to make themselves known, during the reproductive years.
Uterine fibroids affect up to 70–80%¹ of people assigned female at birth by age 50. However, not everyone experiences symptoms, and many fibroids go undiagnosed. Fibroids are most commonly diagnosed in people between their 30s, 40s, and 50s¹,², but they can develop earlier.
While fibroids are common across all racial and ethnic groups, studies show that Black women² are more likely to develop fibroids at a younger age, have larger or more numerous fibroids, and experience more severe symptoms compared to other groups.
Fibroids might be more common for you if you have a combination of the contributing factors on the list above (the question right before this one).
1) https://pmc.ncbi.nlm.nih.gov/articles/PMC3874080/ - The Health Disparities of Uterine Fibroids for African American Women: A Public Health Issue
2) https://pmc.ncbi.nlm.nih.gov/articles/PMC6247381/ - Burden, Prevalence, and Treatment of Uterine Fibroids: A Survey of U.S. Women
What are the symptoms of fibroids?
While fibroids can develop in anyone with a uterus, not everyone will experience symptoms. Because fibroids don’t always cause noticeable symptoms, sometimes they’re only discovered during routine gynecological exams, ultrasounds, or pregnancy-related checkups.
Common fibroid symptoms:
Heavy or prolonged menstrual bleeding¹
Bleeding between periods²
Anemia¹ (this means you don’t have a low amount of red blood cells; it can make you feel tired)
Having a heavy “full” bulky feeling in your lower pelvic region¹
Pelvic pain²
Frequent urination or difficulty emptying the bladder¹
Constipation, diarrhea, and bloating³
Pain during intercourse¹
Lower back pain¹
Difficulty conceiving, multiple miscarriages, early labor¹
Higher likelihood of needing a C-section¹
My story: For me, the crazy part is that for years I just assumed that it was normal to have really bad period cramps. I didn’t even know that fibroids were a thing. Over time, my periods became incredibly heavy and painful. An ultrasound and MRI revealed that I had numerous fibroids. After I had my fibroids treated, all of my period cramps went away, and my period got much shorter and lighter. I can’t promise that that will happen for you too, but it was such a dramatic 180° turnaround for me, that it made me wonder if all those years of “period cramps” were actually fibroid pain instead. Just saying!
1) https://www.nichd.nih.gov/health/topics/uterine/conditioninfo/symptoms - What are the symptoms of uterine fibroids?
2) https://pmc.ncbi.nlm.nih.gov/articles/PMC3342149/ - Prevalence, symptoms and management of uterine fibroids: an international internet-based survey of 21,746 women
3) https://pmc.ncbi.nlm.nih.gov/articles/PMC5476627/ - Patient-reported prevalence and symptomatic burden of uterine fibroids among women in the United States: findings from a cross-sectional survey analysis