Fibroids, also called leiomyomas, are noncancerous tumors that grow in the womb. Fibroids do not always cause symptoms, but in severe cases they can affect pregnancy or fertility.

In most cases, women with fibroids do not realize that they have them, as the growths are too small to cause noticeable complications. However, larger fibroids may affect conception, fetal development, or delivery.

A woman with fibroids during pregnancy clutches her back while sitting on her bed.Share on Pinterest
While a pregnant person may not notice small fibroids, large fibroids may lead to pregnancy complications.

Fibroids often go unnoticed, as they do not always produce signs or symptoms.

In those who are symptomatic, the main indication of fibroids is abnormal bleeding in the form of heavy or extended menstrual bleeding.

Typical symptoms of fibroids during pregnancy include:

  • severe cramps, similar to menstrual cramps
  • widespread pain and tension in the stomach
  • digestion problems, such as constipation
  • increased need to urinate, if the fibroids exert pressure on the bladder

Women may also experience difficulty urinating or back pain, but these symptoms are relatively uncommon.

Fibroids do not usually significantly affect pregnancy.

However, they can sometimes cause:

  • pregnancy loss
  • preterm labor
  • premature rupture of fetal membranes (PROM), leading to the water breaking early
  • hemorrhage soon before delivery
  • malpresentation, where the fetus is not in the right position
  • obstructed labor
  • hemorrhage following delivery
  • necrosis, disrupting the blood supply or causing cell death

Fibroids can sometimes prevent pregnancy by causing infertility. Researchers are still investigating how this happens, but they think that the size and position of the fibroids determine the extent of their effect on the body.

Fibroids may affect conception by obstructing the fallopian tubules — the channels that an egg passes through before a sperm fertilizes it.

A fertilized egg may not be able to attach to the uterine wall if the fibroids get in the way.

A doctor may recommend various surgical procedures to treat fibroids in pregnancy.

In cases where fibroids are particularly large, which can have critical implications, a surgeon may perform a myomectomy, removing the fibroids during pregnancy. However, this is rare, as the surgery can result in further complications.

Removing fibroids during a cesarean delivery is becoming more common, but it is still risky. As a result, it only takes place if it is necessary.

If possible, the safest option is to wait until after delivery to remove the growths.

Hysterectomy is currently the main procedure that surgeons perform to treat fibroids, as it is the only treatment that is definitively effective, and it eliminates the risk of fibroids returning. However, as a hysterectomy removes the uterus, pregnancy will no longer be possible for those who undergo the surgery.

If a doctor identifies fibroids before conception, they can treat them before the woman becomes pregnant. However, the available treatments are temporary and may not be effective.

A woman may undergo:

  • hormone therapy
  • surgery to remove the fibroid
  • high intensity ultrasound treatment
  • uterine fibroid embolization, which is a procedure that restricts the blood vessels supplying the fibroids

Hormone treatments include forms of birth control, such as pills and implants, and taking gonadotropin-releasing hormones (GnRH), usually as a shot.

Different hormonal contraceptives are available, but health experts currently recommend using the levonorgestrel intrauterine device (IUD) for fibroids, as it has the fewest side effects. However, scientists are still researching how hormonal contraceptives work against fibroids, as there is not currently enough knowledge on the subject.

The GnRH leuprolide may be an effective temporary fix, as it can shrink fibroids by causing the uterus to decrease in size. However, women cannot take this treatment for more than 6 months due to the side effects.

Women may be able to lower their risk of developing fibroids by maintaining a healthful diet and minimizing the time that they spend in polluted environments. Artificially sweetened, processed, and preserved food products may increase the chances of developing fibroids.

In most cases, fibroids are not harmful.

Women should see a doctor if they are trying to conceive and are concerned that they may have fibroids.

Those with diagnosed fibroids who become pregnant should inform their doctor of this condition. The doctor can then monitor any implications during fetal development and treat uncomfortable symptoms.

Regardless of pregnancy, it is important to see a doctor if severe abnormal bleeding occurs, as this may lead to iron deficiency anemia or other complications.

Fibroids are common, with experts estimating that they affect 40–80% of women. Most of the time, the growths will have no effect and will not require treatment, but they can sometimes affect fertility.

The outlook for pregnant women with fibroids varies greatly among individuals. If fibroids pose a risk to the health of the pregnancy, the woman may require surgery.

The only definitive treatment for fibroids is hysterectomy. Therefore, if women have fibroids during pregnancy, they should wait until after delivery, if possible, before getting treatment for the growths.