How Do Fibroids Affect Pregnancy?

Fibroids are benign tumors that grow in the uterus that can affect fertility and the ability to conceive. Uterine fibroids are common during a woman’s childbearing years, affecting nearly 30% of women between the ages of 25 and 44. Roughly 20-80% of women will develop non-cancerous fibroids by age 50.

Most women who get fibroids will experience no effects during pregnancy, but 10-30% of women with fibroids develop complications while pregnant.

Fibroids in the First Trimester of Pregnancy

If you develop fibroids during pregnancy, it’ll most likely happen during the first trimester (first three months). Fibroids need the hormone estrogen to grow and estrogen production increases during pregnancy. The most common complication of fibroids is pain, but there are other complications that can occur due to fibroids that include:

• Bleeding and pain. In a study of more than 4,500 women, researchers found that 11% of women with fibroids also had bleeding, 59% just experienced pain, and 30% of the women had both pain and bleeding.
• Miscarriage. The chances that women with fibroids will miscarry during the first trimester are 14% versus 7.6% for women without fibroids. And for women with multiple fibroids, those chances go up even more.

If you develop fibroids during pregnancy, it’ll most likely happen during the first trimester.

Fibroids in the Second and Third Trimester of Pregnancy

As the baby grows, the uterus expands, which can push against fibroids. Some of the complications that can be caused by fibroids the second and third trimester include:

• Fetal growth restriction. Due to their size, larger fibroids can prevent a fetus from growing fully because of the reduced amount of space in the womb.
• Placental abruption. Placental abruption happens when the placenta breaks away from the uterine wall after being blocked by a fibroid. This reduces vital oxygen and nutrients.
• Preterm delivery. The pain that commonly happens due to fibroids can cause contractions, which can result in an early delivery.
• Cesarean delivery. WomensHealth.gov estimates that women with fibroids are six times more likely to need a cesarean delivery than women without fibroids.
• Breech position. Because of the abnormal size of the cavity caused by fibroids, the baby might not be able to align correctly for a vaginal delivery.
• Miscarriage. According to the National Institutes of Health, the chances for miscarriage are doubled in women with fibroids.

Fibroids During Delivery

Having fibroids increases your chances of having a cesarean section because they can block the birth canal, restrict the uterus’ ability to contract, and slow down the progress of labor. For these reasons, women with fibroids are six times more likely to need a cesarean section.

While fibroids can affect the delivery process, the health of the baby is typically unaffected.

Fibroids After Pregnancy

Fibroids usually shrink after pregnancy. Researchers have found that, three to six months after delivery, 70% of women saw their fibroids shrink by more than 50%.

Learn More About Fibroids and Pregnancy with Baptist Health

If you have additional questions about fibroids and pregnancy, contact the Baptist Health Women’s Services team to schedule an appointment.