If you’ve just learned you have a fibroid, you’re far from alone. Uterine fibroids affect up to 7 in 10 women of child-bearing age. And though the thought of having one might send off alarm bells, the comforting truth is they’re usually harmless.

However, it’s possible for a fibroid to make it harder to conceive, and having one can potentially increase the chance for complications once a woman is pregnant. Here’s what you should know about these growths, whether you’re trying for a baby or already have one on the way.

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Key Takeaways
  • Fibroids are common and usually harmless. Uterine fibroids affect many women of reproductive age and are almost always noncancerous. They often cause no symptoms and are frequently discovered during pelvic exams or pregnancy ultrasounds.
  • Most women with fibroids can get pregnant and have healthy pregnancies. While fibroids can occasionally make conception more difficult or raise the risk of complications like preterm birth or C-section, the majority don’t interfere with fertility or delivery.
  • Monitoring is usually all that’s needed. During pregnancy, fibroids are typically managed with symptom relief and regular check-ins. Providers keep an eye on the size and location of the fibroids, and treatment usually isn’t necessary.

What are uterine fibroids?

Uterine fibroids are knotty masses of muscle and fibrous tissue that grow in and around the wall of the uterus. They’re also called myomas or leiomyomas.

You may have just one fibroid or many of them, and they can be different sizes — from small, pea-size growths to masses larger than 6 inches. A small fibroid can grow quickly, or it can expand slowly over a number of years, according to the American College of Obstetricians and Gynecologists.

Fibroids are nearly always benign (non-cancerous) tumors and are very common. According to the American Society for Reproductive Medicine (ASRM), they’re found in up to 70% of women of reproductive age.

What causes uterine fibroids?

Experts don’t know for sure what causes fibroids, though hormones (like estrogen and progesterone) are thought to play a role. They also seem to be more common in women who:

  • Have a family history of fibroids
  • Are between 30 and 40 years old (though they can happen at any age)
  • Are Black
  • Are obese
  • Have early menstruation onset
  • Eat a diet higher in red meat and lower in vegetables

What are the symptoms of uterine fibroids?

Fibroids often go unnoticed, sometimes only getting picked up during a pelvic exam or prenatal ultrasound.

“I just went for an ultrasound today at 6w2d and they found a 9 centimeter fibroid,” says What to Expect Community member Mghhh. “I was very surprised because I never had any symptoms of fibroids in the past.”

But in some cases fibroids can cause symptoms. These may include:

During pregnancy, the most common symptoms of fibroids are pain, vaginal bleeding, and pelvic pressure, particularly in the second and third trimester.

Can you get pregnant if you have fibroids?

First, the good news: It’s rare for fibroids to cause fertility problems. Occasionally though, the growths can make it harder to get pregnant. Between 5% and 10% of women who seek help for infertility have fibroids, according to ASRM.

Depending on its size and location, it’s possible for a fibroid to cause a fallopian tube blockage or change the shape of a woman’s cervix or uterus, making it harder for sperm to reach and fertilize an egg. In some cases fibroids can also affect the ability of an embryo to successfully implant on the uterine wall. And fibroids may affect the growth and positioning of the baby.

If you have fibroids and are having trouble conceiving, ASRM recommends both you and your partner see a fertility specialist. (It’s possible for fibroids to be the culprit, but the problem could also be caused by other factors related to you or your partner.) If the fibroid turns out to be the cause, it can be treated to improve your chances of getting pregnant.

Can fibroids cause problems during pregnancy?

Fibroids aren’t typically problematic during pregnancy. And when they do cause symptoms, they’re usually minor — some abdominal pain, light vaginal bleeding, or a feeling of pressure on the bladder.

Occasionally, estrogen may promote the growth of uterine fibroids. Since pregnant women churn out lots of the hormone — it helps the uterus (and your breasts) grow, maintains the uterine lining, and increases blood flow — fibroids can sometimes grow during pregnancy.

If a fibroid grows, says ASRM, it usually does so in the first 12 weeks of pregnancy. But the majority tend to shrink back down to their original size after giving birth.

Fibroids do, ever-so-slightly, raise the risk of preterm delivery, and they can sometimes push the baby into an odd position for delivery or block off part of a baby's exit path through the cervix (which makes for a slightly higher chance of C-section).

Both women who have fibroids and those who have had fibroids before becoming pregnant may be more likely to need a C-section as well, so you should let your practitioner know if that was the case for you.

While these increased risks can be unsettling to think about, they shouldn’t be a huge worry. Your provider will keep a close eye on the size and placement of your fibroid throughout your pregnancy, and the majority of these growths don’t affect your ability to have a healthy delivery and baby.

Some pregnant moms are comfortable enough with their fibroids that they name them! “Mine is called Cyst — my daughter’s ‘cyster,’ says What to Expect Community mom marimene. Another mom, miyuluna, named her large fibroid Uncle Gustave and her smaller one Auntie Gildebert.

Keep track of your prenatal appointments, fibroids, kick counts, and more in the My Journal feature of our What to Expect app.

How are fibroids treated during pregnancy?

Because fibroids aren’t usually problematic, they’re mostly treated conservatively during pregnancy and don’t require a specialist. Often symptoms like discomfort or occasional bleeding are managed with bed rest and hydration.

Nonsteroidal anti-inflammatory drugs (NSAIDs) or other pain medications may be prescribed, but they should be used for short periods and only under the supervision of your health care provider.

It’s possible for fibroids to be removed surgically during pregnancy. But since surgical procedures can pose risks to both a woman and her baby, they’re typically only performed in cases where the fibroid is very large or fast-growing.

When to talk to a doctor about fibroids

Fibroids are usually harmless and don’t always cause discomfort. That said, it’s still important to keep your doctor informed about your fibroid history and symptoms, since fibroids have the potential to affect your fertility and can cause pregnancy complications. Call your doctor if you’re experiencing vaginal bleeding, abdominal pain, or pelvic pressure, whether you know it’s related to a fibroid or not.

If you’re pregnant and previously had a fibroid removed by another provider, let your current doctor know about it. That way, they can monitor you for possible (but unlikely) complications or risks.

Finally, see your doctor if you have a fibroid or a history of fibroids and are having trouble getting pregnant. Together you can determine if the fibroid is getting in the way of your ability to conceive, and if so, how to treat it.

Hearing the word “fibroid” can be scary, especially when you’re trying to get pregnant or already expecting. But for most women, fibroids are just another closely watched part of pregnancy, not a roadblock. With regular monitoring and guidance from your provider, the odds are very good that you’ll go on to have a healthy pregnancy and baby.