How Do Fibroids Affect Pregnancy?

Fibroids occur in roughly 20% of women of childbearing age. During pregnancy, fibroids can increase the risk of premature delivery or miscarriage by affecting the baby’s position in the uterus.

Fibroids occur in roughly 20% of women of childbearing age. They are growths that are made up of muscle tissue and are found in the uterus. Fibroids are almost always benign Fibroids form when a muscle cell multiplies enough to form a tumor.

While fibroids are noncancerous, they can cause complications by altering the size and shape of the uterus and cervix. Fibroids may cause symptoms or require treatment based on how many you have, where they are located within the uterus, and how large they have grown.

Depending on their size and location, fibroids can affect pregnancy and fertility. While the majority of women with fibroids are not infertile, there are several ways fibroids can affect the reproductive process, including:

• Impacting the shape of the uterus in such a way that some sperm are blocked from entrance
• Affecting the shape of the uterus in a way that impacts the embryo
• Blocking the sperm or eggs from fallopian tubes
• Disrupting uterine lining
• Impeding blood flow to the uterus or baby
• Disrupting fertilization or growth of the baby 

During pregnancy, fibroids can increase the risk of premature delivery or miscarriage by affecting the baby’s position in the uterus. Women who have fibroids or have had fibroids removed should discuss their options and birth plan with their doctor. Many women who are affected by fibroids opt for a cesarean section to deliver their baby.

While many women notice mild or no symptoms with fibroids, some women experience a variety of noticeable symptoms, such as:

Heavy bleeding 

Some women who develop fibroids may have very heavy bleeding during menstruation. Heavy bleeding often occurs in tandem with painful periods and cramps. Irregular or excessively heavy bleeding may lead to anemia and other complications. 

Feeling of fullness

One symptom of fibroids is a sensation of fullness in the lower stomach area. This is often accompanied by significant bloating of the lower abdomen. 

Excessive urination

Some women who have fibroids may notice that they have a frequent urge to urinate.

Pain during sex

One of the most common signs or symptoms of fibroids is pelvic pain during sex. The pain may range from constant to intermittent and from a dull ache to sharp pain.

Lower back pain

Lower back pain — especially recurring pain — can be an indicator of fibroids in the uterus or cervix. 

Pregnancy complications

FiResearch shows that women who have fibroids may be up to six times more at risk for needing a cesarean section than women who do not. Beyond this, fibroids can cause a number of complications during pregnancy and labor, such as:

• Miscarriage
• Affect on the baby’s birthing position
• Damage to the placenta
• Premature birth
• Bleeding

Infertility

In rare cases, a woman with fibroids may not be able to become pregnant. Between 5% and 10% of infertile women have had uterine fibroids. However, most women who have fibroids in their uterus will eventually become infertile. Fertility interventions, such as in vitro fertilization (IVF), are less effective in women with fibroids. It is important to ask your doctor about how fibroids can affect your fertility. 

The cause of fibroids is not known. However, research indicates that genetic factors and age play a significant role. While the cause of fibroids has yet to be determined, studies show that fibroids are more likely to occur in:

• Women who are obese
• Women who have a mother or sister with fibroids
• Women who have not yet been pregnant
• Black women

Researchers are still trying to understand why fibroids develop. They have also found that women who have already had multiple children and women who have used hormonal birth control are less likely to develop fibroids. 

Your doctor may be able to diagnose fibroids when you see them for your routine pelvic exam — they can feel the fibroid with their hands during a typical exam. 

Your doctor may recommend additional imaging or surgical testing to confirm their diagnosis. Tests may include:

• Ultrasound
• MRI
• Cat scan
• X-rays
• Laparoscopy 
• Hysteroscopy

Currently, treatment for fibroids during pregnancy focuses on conservative treatment — typically prescription medication, but in rare cases, surgery.

Possible treatment of fibroids include:

• Hormonal birth control
• Anti-inflammatory drugs
• Hormone therapy
• Surgery to reduce or remove fibroids