Fibroids (leiomyoma) are muscular tumors that grow in the wall of the uterus (womb). Fibroids are almost always benign (not cancerous) and can grow as a single tumor, or there can be many of them in the uterus. They can be as small as an apple seed or, in unusual cases they can become very large, up to the size of a grapefruit.
Are fibroids common?
It’s estimated that about 20-80% of women develop fibroids by the time they are 50 years old. It’s hard to know definitively how many women have fibroids, considering so many women don’t have symptoms, and this is why the number varies so drastically. Fibroids are most common in women in their 30s, 40s, and early 50s. Not all women with fibroids have symptoms but women who do have symptoms, like pain and heavy menstrual bleeding, often find fibroids hard to live with. Fibroids can also put pressure on the bladder, which can cause frequent urination, or put pressure on the rectum. If the fibroids get very large, they can cause the abdomen to enlarge, which can make a woman look like she is pregnant.
What factors increase the risk of fibroids?
It is not yet known definitively what causes fibroids. Medical professionals have deduced that more than one factor could play a role. These factors could be:
● Genetic (runs in families)
○ Having a family member with fibroids increases the patient’s risk. If a woman’s mother had fibroids, her risk of having them is about 3x higher.
Other factors can also play a role:
● Age. Fibroids become more common as women age, especially as they go through menopause. However, it was also noted that after menopause, fibroids typically shrink.
● Ethnicity. Black women are more likely to develop fibroids than white women.
● Obesity. Women who are overweight have a higher risk of developing fibroids. For a morbidly obese woman, their risk is 2-3x greater than the average woman.
● Eating habits. Eating a lot of red meat, like beef and pork, is linked with a higher risk of fibroids. Additionally, eating plenty of green vegetables seems to help women prevent fibroids.
However, considering there is no concrete explanation as to what causes fibroids, we also don’t know definitively what causes them to grow or shrink. What we do know, is that they are controlled by the hormones estrogen and progesterone. Studies have shown that fibroids grow rapidly during pregnancy when hormone levels are high and shrink during menopause or when anti-hormone medication is used.
Where do fibroids grow?
The majority of fibroids grow in the wall of the uterus. Experts put them into three groups based on their location in the body:
● Submucosal fibroids grow into the uterine cavity.
● Intramural fibroids grow within the wall of the uterus.
● Subserosal fibroids grow on the outside of the uterus.
Some fibroids, called pedunculated fibroids, grow into the cavity of the uterus or out from the surface of the uterus.
What are the symptoms of fibroids?
Most women with fibroids don’t have any symptoms, but some women can have:
● Heavy bleeding (which is sometimes severe enough to lead to anemia) or painful menstrual cycles
● A feeling of fullness in the pelvic area (lower stomach area)
● Enlargement of the lower abdomen
● Frequent urination
● Pain during sex
● Lower back pain
● Complications during pregnancy and labor
● Rarely, patients experience reproductive problems, such as infertility
Which pregnancy complications are more common in women with fibroids?
Women with fibroids are more likely to have complications during pregnancy and delivery. However, this doesn’t mean there will definitely be problems and most women with fibroids have normal pregnancies.
The most common complications in pregnant women with fibroids are:
● Mandatory cesarean section. The risk of requiring a c-section is 6x greater for women with fibroids.
● Baby is breech. The baby is not in the right position for vaginal delivery.
● Labor fails to progress.
● Placental abruption. The placenta breaks away from the wall of the uterus before delivery. When this happens, the fetus doesn’t get enough oxygen.
● Preterm delivery.
It’s important for patients to talk to their obstetrician if they have fibroids and become pregnant. Most women do not need to see an OB who deals with high-risk pregnancies because the majority of obstetricians have had experience dealing with fibroids and pregnancy.
Come back next week for part two where we will be discussing the diagnosis and treatment process for uterine fibroids.