What size of fibroid is dangerous?

Woman with fibroid pain

Are you wondering what size of fibroid is dangerous and if yours are cause for concern? Fibroids can be a source of stress and anxiety for many women, but understanding exactly how they function as well as their potential health implications can help provide peace of mind. In this blog post, we'll review the different sizes, sizes that might signal danger, and more.

Understanding fibroid sizes

Understanding fibroid sizes is crucial in determining the appropriate treatment.

Fibroids are typically classified as small, medium, or large based on their measurements in centimeters.

Small fibroids are generally 1 - 5 centimeters in size, while large fibroids can measure 6 centimeters (or more!) and may require more intensive treatment. If left untreated, large fibroids can affect your uterus, change its shape, and ultimately affect future pregnancy.

In some extreme cases, fibroids weighing more than 20 pounds have been reported. However, it's important to note that the weight of a fibroid alone may not necessarily indicate its potential impact on an individual's health or the severity of symptoms experienced.

Factors that influence fibroid size

The size of these growths can vary greatly and are influenced by a number of factors.

Race

One study found that African-American women have larger fibroids and fibroids that weigh more when compared to White women.

No pregnancies in your past

The same study found that women who hadn’t been pregnant (called ‘nulligravidity’) had larger fibroids. Women who had been pregnant multiple times in the past experienced fewer fibroids and smaller sized fibroids (1).

Vitamin D levels

Another study found that women who had lower Vitamin D levels had larger fibroids (2).

Determining dangerous fibroid sizes

It’s difficult to say what size of fibroid is dangerous because size alone isn't the only factor to consider. The location of the fibroid in the uterus, as well as individual health factors, can also play a role.

According to Dr. Valerie Lynn Baker, M.D., uterine fibroids can sometimes affect the mode of delivery of a baby. For instance, if a woman has a fibroid located in the lower part of her uterus, it could potentially make it difficult for the cervix to open completely during labor. This situation may complicate the delivery process and could possibly lead to a scenario where a C-section becomes necessary, presenting additional challenges for the mother.

It is important for women to seek medical attention if they suspect they may have large fibroids, as prompt treatment may be necessary to prevent further complications. As with any health concern, early detection and treatment is key to a positive outcome.

Uterine fibroid embolization

Fibroid treatment at MIMIT Health

Uterine fibroid embolization (UFE) has rapidly become a popular and effective treatment for fibroids that avoids the risks of a hysterectomy.

It’s minimally invasive, meaning there’s no big cuts and shorter recovery time.

It works by blocking blood flow to the fibroids, effectively causing them to shrink.

The procedure is typically performed under local anesthesia and involves inserting a small catheter, which is then guided to the uterine artery. The procedure is highly effective for most women with fibroids, and offers the added benefits of a shorter recovery time, reduced pain, and fewer complications when compared to traditional surgical procedures.

As a result, patients can experience significant relief from symptoms such as heavy bleeding, pain, and discomfort.


  1. Moorman PG, Leppert P, Myers ER, Wang F. Comparison of characteristics of fibroids in African American and white women undergoing premenopausal hysterectomy. Fertil Steril. 2013 Mar 1;99(3):768-776.e1. doi: 10.1016/j.fertnstert.2012.10.039. Epub 2012 Nov 27. PMID: 23199610; PMCID: PMC3632655.

  2. Sabry M, Halder SK, Allah AS, Roshdy E, Rajaratnam V, Al-Hendy A. Serum vitamin D3 level inversely correlates with uterine fibroid volume in different ethnic groups: a cross-sectional observational study. Int J Womens Health. 2013;5:93-100. doi: 10.2147/IJWH.S38800. Epub 2013 Feb 27. PMID: 23467803; PMCID: PMC3589082.

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Fibroids and Pregnancy: Understanding the Link