Uterine fibroids at a glance
- Uterine fibroids are noncancerous, smooth muscle tumors in or on the uterus that may affect fertility and hinder IVF (in vitro fertilization).
- Patients with uterine fibroids considering IVF may be advised to treat the fibroids first.
- Fibroids are very common and often cause no symptoms, though in serious cases, they may cause pain, infertility and complications during pregnancy and birth.
- Treatment methods for uterine fibroids include surgical and nonsurgical options.
What are uterine fibroids?
Uterine fibroids, also known as leiomyomas or myomas, are noncancerous muscle tumors that originate from the smooth muscle wall of the uterus that affect 20 percent of all women of reproductive age. They are much more likely to affect non-white women.
This is because women with dark skin color generally have lower levels of vitamin D. Low vitamin D levels are associated with a higher likelihood of getting uterine fibroids. As a preventive measure, some doctors may recommend that women with an increased risk for fibroids take vitamin D supplements.
Uterine fibroids tend to develop due to genetics and are thus more likely if there is a family history. They have an increased rate of occurrence as women get older and go through menopause. It is estimated that up to 80 percent of all women will experience uterine fibroids in one form or another by the time they reach age 50.
A uterine fibroid develops when a muscle cell within the uterus spontaneously multiplies to form an abnormal, benign (noncancerous) growth. A fibroid may be broadly categorized as subserous (on the outer wall of the uterus), intramural (within the wall of the uterus) or submucosal (growing into the uterine cavity).
Subserous uterine fibroids are the most common type, comprising 55 percent of all cases. Forty percent of fibroids are classified as intramural and just 5 percent are found to be submucosal. Fibroids may cause symptoms or affect a woman’s fertility depending on their size, location and number.
Uterine fibroids symptoms
Fibroids will often present no symptoms at all, but more serious cases may cause pain and other unpleasant side effects. In some cases, they may also cause infertility and issues with pregnancy and giving birth, such as miscarriage, preterm delivery, increased risk of needing a cesarean section and excessive bleeding after giving birth. Symptoms of uterine fibroids include:
- Ongoing pain and pressure
- A persistent sense of fullness in the abdominal region
- Heavy or painful menstruation
- Frequent urination
- Lower back pain
- Painful intercourse
- Infertility or difficulty conceiving
- Pregnancy and labor complications.
If a patient or physician suspects the presence of uterine fibroids, they can be easily identified in an ultrasound exam or MRI.
How do uterine fibroids affect fertility?
In a minority of cases, uterine fibroids can cause infertility. This happens most often when fibroids are found within the uterine cavity (submucosal) or when they are very large (greater than 5 centimeters in diameter). In these cases, the fibroids cause structural changes inside the body that impact fertility, including:
- Cervix shape changes, limiting the number of sperm that enter the uterus
- Uterus shape changes, affecting implantation of an embryo
- Blockage of fallopian tubes
- Compression of the uterine cavity
- Reduced blood flow to the uterus, resulting in embryo implantation issues
- Fibroids can degenerate, and the dead tissue produces increased inflammation, which can negatively affect fertility.
How do uterine fibroids affect IVF outcomes?
The medical journal Expert Review of Obstetrics and Gynecology cites multiple research studies demonstrating that patients with fibroids have lower IVF success rates. But there are some important caveats.
Researchers tend to recommend the removal and treatment of submucosal fibroids prior to an IVF cycle. Intramural fibroids that extend to the uterine cavity or compress or distort the uterine cavity can also negatively impact IVF pregnancy rates.
There is less conclusive evidence that the other more common types of fibroids adversely affect IVF success. However, this does not mean that only these types of fibroids negatively affect a woman’s overall fertility.
Because fibroids often appear in multiples and vary greatly in shape, size and location, the effect of a patient’s fibroids on her fertility and outlook for IVF treatment is evaluated on a case-by-case basis. A patient seeking IVF treatment may be advised on various methods of fibroid removal, which may increase the chance of a successful IVF cycle and pregnancy.
How do uterine fibroids affect pregnancy and birth?
Many women diagnosed with fibroids have normal, uncomplicated pregnancies. However, studies have shown that fibroids are associated with lower pregnancy rates, lower rates of live birth, and elevated risks of miscarriage, as well as bleeding and pain during pregnancy. Additionally, women with fibroids have 6 times the likelihood of needing to deliver via caesarean section.
Fibroid growth is stimulated by estrogen levels, which naturally increase during pregnancy. For this reason, fibroids will sometimes grow in size during the course of a pregnancy, and then decrease after a woman gives birth.
Treatment of uterine fibroids
Not all women with fibroids have symptoms or need treatment. Intervention is indicated when women have symptoms affecting their quality of life. Treatment may also be appropriate when fibroids may be affecting a woman’s ability to conceive and have a healthy pregnancy.
Different treatment methods are advised depending on the severity of symptoms as well as a patient’s goals. For example, some of the treatments below are not advised for women who are trying to get pregnant or wish to get pregnant in the future.
Surgical procedures to remove uterine fibroids involve some options. Myomectomy is particularly appropriate for women considering becoming pregnant after uterine fibroid removal, as it leaves the uterus intact.
Other surgical options include hysterectomy (removal of the uterus), hysteroscopy and laparoscopy, including robotic laparoscopy.
Nonsurgical treatments include oral medications, uterine artery embolization and MRI-focused ultrasound therapy.