According to the National Institutes of Health, 70-80% of women will have uterine fibroids by the age of 50 and between 20-50% of women of childbearing age have fibroids. The good news is that fibroids are benign (non-cancerous) uterine growths and in most cases, do not require treatment. Many people often worry about uterine fibroids and pregnancy and, while there are a few additional risks, they're rare and often treatable. Here's what you should know.
What are uterine fibroids?
Uterine fibroids are abnormal growths that consist of muscle cells and fibrous tissues that form a mass within the uterus. They usually don't become cancerous. New insights into what causes fibroids show the presence of mutations inside the uterine wall cell that lead to unbridled growth. The mutation responsible for over 70% of fibroids is in the Mediator Complex Subunit 12 gene (MED12). Factors that increase the risk of development of fibroids include: African ancestry, increasing age, family history of uterine fibroids, time since last birth, hypertension, and consumption of food additives and soybean milk. Reference is SK Laughlin-Tommaso, EA Stewart. Moving Toward Individualized Medicine for Uterine Leiomyomas. Obstetrics and Gynecology. 2018;132:961-971.
Most women won't even know they have them. If you do become pregnant, uterine fibroids can present some challenges. Some women will experience more pain during their pregnancies because of them or fertility challenges beforehand.
Overall, uterine fibroids are generally harmless and don't interfere with a healthy pregnancy or fertilization. By working with a highly-skilled physician who can monitor the growths and treat them if necessary, you can greatly reduce any risks.
Types of uterine fibroids
You can grow uterine fibroids inside or outside your uterine walls, or even within the uterine walls themselves.
There are four types of fibroids:
- Intramural: Grow within the uterine wall
- Submucosal: Grow under the lining of the uterine cavity
- Subserosal: Grow on the outer uterine wall
- Pedunculated: Grow on a stalk either inside or outside of the uterus
What are symptoms of uterine fibroids?
Many women don't even realize they have uterine fibroids until they get an ultrasound. Most are non-symptomatic, with no physical signs.
For those who do have them, uterine fibroid symptoms can include:
- Abnormally heavy or long menstrual cycles
- Clotting during menstruation
- Bleeding between periods and irregular periods
- Pain with deep penetration during intercourse
- Bladder irritability, or overly frequent urination
- Frequent urinary tract infections
- Painful bowel movements
- Pelvic pressure or pain
- Lower back pain
- Leg pain
- Feeling of pressure or heaviness in belly or rectum
Women who experience severe uterine fibroids that protrude into the uterine cavity can have additional complications. This protrusion can erode the endometrial lining away and produce irregular or continuous bleeding (called menometrorrhagia).
Do fibroids affect fertility?
Many women will conceive naturally if they have fibroids, but fibroids can affect your ability to get pregnant. The size and location of your fibroids, among other factors, will determine whether or not it affects your fertility.
Uterine fibroids may impact fertility in a number of ways because they can:
- Distort cervix and uterus, negatively impacting gamete movement or embryo implantation
- Block fallopian tubes
- Negatively impact the receptivity of the uterine lining
Fibroids that are inside the uterine cavity (submucosal) or those that are larger than six centimeters in diameter have a higher likelihood of impeding conception.
Can you get pregnant if you have uterine fibroids?
Yes, most women with uterine fibroids can still get pregnant naturally.
Most women with fibroids will not be infertile, however, it is best to consult with a fertility specialist to determine if your fibroids are hampering your ability to conceive. By removing large or problematic fibroids before conception, you can effectively reduce any uterine fibroids and pregnancy risks.
Can fibroids cause a miscarriage?
Conventional wisdom suggested that, yes, fibroids could lead to a higher risk of miscarriage. The latest research from Vanderbilt University in 2017, following a ten-year study of 5,500 women, found that women with fibroids are not actually at an increased risk for miscarriage.
Katherine Hartmann, M.D., Ph.D., lead researcher, noted that:
“We find women with fibroids are not at increased risk of miscarriage. Women with fibroids had identical risk of miscarriage as women without fibroids when taking into account other risks for pregnancy loss. We were stunned.”
For women with fibroids, this does mean one less thing to worry about during their pregnancy.
Do fibroids affect pregnancy?
When it comes to uterine fibroids and pregnancy, once you're pregnant most doctors recommend only monitoring fibroids and not removing them. This is due to risks to the fetus.
Although most women with fibroids do not experience complications during pregnancy, up to a third of pregnant women do have abdominal pain accompanied by light vaginal bleeding. Most doctors will treat this with mild pain relievers, rest, or other minimal interventions to manage symptoms.
Depending on the severity of your fibroids, there may be additional risks but most studies show that these are rare. Fibroids do not generally affect your risk of:
- Fetal growth problems
- Fetal abnormalities
- Placental problems
- Heavy bleeding after delivery
Caesarean delivery (C-section) is more common among women who have fibroids, though. In some severe cases, they can also cause very preterm births. This is especially true if your fibroids rapidly increase in size after pregnancy begins.
I have fibroids—what should I do?
If you are trying to conceive and are experiencing an irregular menstrual cycle, excessive bleeding, or other uterine fibroid symptoms, you should schedule an appointment with your doctor (if you're in the Gulf South, reach out to us at the Fertility Institute!)
Get a diagnosis
Your doctor can check the size and location of your fibroids to help ensure a healthy delivery. They can easily identify a large fibroid by a simple bi-manual vaginal examination or transvaginal ultrasound.
Further, if a fibroid appears to be impinging on your endometrial cavity, your doctor can insert a hysteroscopy (a telescope-like instrument) into your uterine cavity to determine whether the fibroid is intramural and submucosal.
Consider your treatment options
Generally, fibroids are only treated if they are causing severe symptoms, especially heavy or long menstrual periods. Your doctor will usually only monitor small, asymptomatic fibroids for growth instead of removing them. If you're not planning on getting pregnant, hormonal birth control can help regulate these symptoms.
If you are starting fertility treatments, such as in vitro fertilization (IVF), your doctor may recommend removing any large fibroids or submucosal fibroids in order to decrease the chance of implantation failure or later pregnancy complications. Intramural and subserosal fibroids are removed by laparoscopic resection or via an abdominal incision.
If you're in the Gulf South and are interested in learning more about uterine fibroids and pregnancy, schedule an appointment to learn more.
Updated Blog. Originally posted August 24, 2016.