Uterine Fibroids


The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

What are uterine fibroids?

The term uterine fibroids refers to leiomyomas or simply myomas, which are benign tumors that can form in the smooth muscle of the wall of the uterus. Leiomyomas can exist before, during, or after pregnancy and while they are not cancerous, they can cause problems because they occupy space in the uterus and interfere with its normal ability to stretch evenly during pregnancy.

How common are uterine fibroids in pregnancy?

Uterine fibroids are the most common pelvic tumors and the most common benign tumors in women. Approximately 60 percent of women of reproductive age, and 80 percent of women in the course of their lifetimes develop uterine fibroids. Uterine fibroids have been reported as present in roughly 11 percent of pregnancies, although the number is probably higher because only fairly large fibroids produce symptoms.

 How are uterine fibroids diagnosed?

Your doctor can have a strong hint that you may have uterine fibroids based on your reporting of uterine bleeding, especially heavy bleeding during your menstrual cycle, combined with findings on a routine pelvic exam. Blood tests also will be performed to test for hormones and evidence of blood loss. Once this is done, the presence of uterine fibroids can be confirmed by several techniques including hysteroscopy, magnetic resonance imaging (MRI), hysterosonography, and hysterosalpingography.

Do uterine fibroids cause problems during pregnancy?

Generally, uterine fibroids do not cause major problems during pregnancy and its only when the fibroids grow fairly large that they cause problems whether you are pregnant or not. However, the risk of spontaneous abortion (miscarriage) and preterm delivery increase slightly.

Do uterine fibroids during pregnancy cause problems for the baby?

Generally, uterine fibroids do not cause problems for the baby. However, the risks increase slightly for spontaneous abortion (miscarriage), and for preterm delivery, which can lead to some physical problems during infancy and behavioral problems during childhood.

What to consider about taking medications when you are pregnant:

  • The risks to yourself and your baby if you do not treat the uterine fibroids
  • The risks and benefits of each medication you use when you are pregnant
  • The risks and benefits of each medication you use when you are breastfeeding

What should I know about using medication to treat uterine fibroids during pregnancy?

Medications to treat uterine fibroids generally are given outside of pregnancy. These are hormonal treatments, which include gonadotropin-releasing hormone (Gn-RH) agonists, which block the production of estrogen and progesterone as if you were post-menopausal. Oral contraceptives may be prescribed, or a device can be implanted that releases the hormone progestin. Non-hormonal treatments include tranexamic acid, which is taken only on heavy bleeding days to ease menstrual periods, and nonsteroidal anti-inflammatory drugs (NSAIDs) which include ibuprofen, naproxen, and many others. Oral contraceptives must be avoided during pregnancy. NSAIDs should be avoided during the late part of pregnancy.

Who should NOT stop taking medication for uterine fibroids in pregnancy?

Generally, the available medications for uterine fibroids are given only to non-pregnant patients.

What should I know about choosing a medication for uterine fibroids in pregnancy?

You may find Pregistrys expert reports about the individual medications to treat uterine fibroids here. Additional information can also be found in the sources listed at the end of this report.

What should I know about taking a medication for uterine fibroids when I am breastfeeding?

NSAIDs are thought to be relatively safe in mothers who breastfeed. Hormonal treatments for uterine fibroids are likely to be safe, as breast milk is full of the mother’s hormones anyway.

What alternative therapies besides medications are there to treat uterine fibroids during pregnancy?

Watchful waiting is the standard treatment, since most uterine fibroids are small and produce no symptoms, and since fibroids can come and go over time. Various surgical procedures are available to destroy uterine fibroids. These include removing them (myomectomy), destroying them with heat (ablation), electric current or microwave energy, destruction by low temperature or by radiofrequency, or intentional production of clots in the arteries that feed the fibroids (uterine artery embolization).

What can I do for myself and my baby when I have uterine fibroids during pregnancy?

Reassure yourself that most pregnancies proceed normally in the presence of uterine fibroids. In severe cases, work with your physicians and be open to the various treatment options, most of which would be implemented after your pregnancy is complete.

Resources for uterine fibroids during pregnancy:

For more information about uterine fibroids during pregnancy, contact http://www.womenshealth.gov/ (800-994-9662 [TDD: 888-220-5446]) or read the following articles:


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General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.

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