Fibroids & Weight Gain
Symptoms of Fibroids
Uterine fibroids can vary in size from small ‘seedlings’ to large masses that fill the entire abdomen. As fibroids grow, the uterus expands to accommodate them similar to how it expands throughout a pregnancy.¹
As their fibroids grow, women may experience:
• Enlarged uterus
• Unexplained weight gain
• Weight gain around the abdomen and pelvis
Can Fibroids Cause Weight Gain?
Yes, they can! As the fibroids grow in weight, women may notice their weight increasing as well, especially around the abdomen and the pelvis. Therefore, one fibroid symptom can be weight gain.
Fibroid Weight Gain
Growth rates of fibroids vary significantly depending on age and race.² In many cases, fibroids remain small and inconsequential, which is part of the reason why so many women have asymptomatic fibroids. In other cases, fibroids undergo phases of rapid growth, causing visible distention of the abdominal region, weight gain, and pelvic pressure, among other symptoms.³⁻⁴
The location of fibroids can also lead to different symptoms. As they get larger, fibroids can cause mass effect, which is the effect that they have on surrounding tissues and organs as they begin to touch and compress them. The uterus is in close proximity to the rectum and colon along with the bladder, and large fibroids may put pressure on these organs leading to urgency, bloating, and/or pain.
Estimating Uterine & Fibroid Size
Physicians can use methods like the physical exam to estimate the size of your uterus. A normal sized uterus is roughly the size of a small pear and is deep inside the pelvis. As it grows due to fibroids, its size is described as compared to a gravid, or pregnant, uterus. A benchmark that many physicians use is that a 12 week pregnant uterus is felt at the pelvic bone and is the size of a grapefruit, while at 20 weeks the uterus is felt at the umbilicus (around the belly button).⁵ They can use this to estimate the size of the uterus depending on where they feel it in the abdomen. The bigger it is, the more likelihood that the symptoms a woman experiences are worse.
If you see a specialist for your fibroids, you may be asked to obtain an imaging study such as an ultrasound or MRI, which allows your physician to obtain a more exact view of your fibroids. This is particularly helpful if any treatment is planned.
What Causes Fibroids to Gain Weight?
Uterine fibroids are benign smooth muscle tumors which can go through phases of growth and degeneration. Based on the blood flow to each fibroid, their structure can change. This can lead to different types of tissues inside the fibroid. While this is only apparent to specialists who can diagnose and treat them, it may lead to differences in how the fibroids make women feel.
Fibroids have different growth rates depending on how many are present in the uterus and the age of the woman. While a specific growth mechanism is not known, it is known that fibroids respond to the presence of estrogen, a hormone that circulates in women’s bodies and controls many functions. The levels of estrogen decrease during and after menopause, and this is thought to lead to slower growth and sometimes shrinking of uterine fibroids.²
If you've experienced unexplained weight gain, abdominal bloating, or if your stomach is expanding, you may be living with uterine fibroids. You can review other symptoms of uterine fibroids here.
 Duhan, N., & Sirohiwal, D. (2010). Uterine myomas revisited. European Journal of Obstetrics Gynecology and Reproductive Biology, 152(2), 119–125.
 Peddada, S. D., Laughlin, S. K., Miner, K., Guyon, J.-P., Haneke, K., Vahdat, H. L., … Baird, D. D. (2008). Growth of uterine leiomyomata among premenopausal black and white women. Proceedings of the National Academy of Sciences, 105(50), 19887–19892.
 Funaki, K., Fukunishi, H., Tsuji, Y., Maeda, T., & Takahashi, T. (2013). Giant cystic leiomyoma of the uterus occupying the retroperitoneal space. Journal of Radiology Case Reports, 7(12), 35–40.
 F., S., I., I., O., A., R., H., C., D., A., I., … T., R. (2011). Giant uterine leiomyoma. Chirurgia (Bucharest, Romania : 1990), 106(5), 665–668.