Does Your Uterus Really Get Bigger During Your Period?

An ob-gyn weighs in on a viral photo that claims to show the drastic size difference between a menstruating and non-menstruating uterus.

a person suffering from stomach cramps on a sofa
Photo: Getty Images/Charday Penn

It's no secret that that time of the month can be brutal on your body. Some people experience uncomfortable bloating during their period; others deal with breast tenderness and extreme mood swings. But have you ever wondered what goes on in your body during your menstrual cycle? Specifically, what happens to your uterus during your period?

A Facebook page called Apples and Ovaries — run by a self-described holistic nutritional therapist and natural fertility health consultant who only identifies herself by the first name India — claims to have the answer. In a post that was originally shared back in 2012, a photo appears to show someone holding "two life-sized replicas" of a menstruating and non-menstruating uterus. The size difference between the two replicas seems to suggest that the uterus nearly doubles in size during your period.

"This is why we feel so heavy at the beginning of our bleed. Why it can feel like our uterus is about to drop out and hit the pavement (or is that just me?)," reads the caption.

Though the photo has made the rounds on social media multiple times over the last several years, commenters on the original post seem conflicted about its accuracy. "I have noted a SLIGHT difference in the size and texture of the uterus right before or during the menstrual cycle but I believe that is quite an exaggeration," wrote one skeptical commenter. "This is extremely FALSE #fakenews," added another.

Others appear to believe the suggested size difference makes total sense, especially given their own period symptoms: "No wonder we feel so crappy!!" commented one person. "Omg yes that's why it feels extremely sore," said another.

Does your uterus actually get bigger during your period?

In short: yes, but not to the degree suggested in that photo.

See, the uterus — a female reproductive organ located in the pelvis between the bladder and rectum — is typically hollow, pear-shaped, and about the size of a fist, according to the University of Rochester Medical Center. During your period, your body's estrogen levels increase, causing the uterine lining to thicken in preparation for an embryo — meaning, technically, the uterus does slightly swell in size during menstruation, says Sherry Ross, M.D., F.A.C.O.G., an ob-gyn and Summer's Eve ambassador. If conception doesn't happen, the lining sheds (that's when you begin to bleed), the swelling goes down, and your uterus returns to its normal size in a few days, she explains.

In terms of exact stats, the uterus will usually increase in size by about 10–15 percent during your period, making the viral Facebook photo "fictional and not accurate," says Dr. Ross. And, actually, the larger uterus replica in the photo seems comparable to the uterus of someone who's 10-12 weeks pregnant, she adds.

As for those feelings of heaviness and soreness you might experience during your period? The size of your uterus really has nothing to do with that, explains Dr. Ross. Rather, a combination of increased blood flow to the area and fluctuating hormones can cause painful symptoms such as bloating and breast tenderness, she says.

Can an enlarged uterus be a sign of a potential health issue?

How big is a uterus, then? The average uterus measures about 3–4 inches by 2.5 inches, according to the National Uterine Fibroids Foundation. It can grow in size for a number of reasons, though it's not always a sign of something troublesome, notes Dr. Ross. Whether or not uterus growth is cause for concern ultimately depends on the "normal" size of your individual uterus and other symptoms you might be experiencing alongside the change in size. An exam called a transvaginal pelvic ultrasound will allow you to see the exact dimensions of your uterus, says Dr. Ross.

For instance, if the duration or general nature of your period symptoms have also changed (particularly to the point of being disruptive to your daily life), and/or other nearby organs — such as the bladder and bowel — appear to be affected, it's best to check things out further with your ob-gyn, suggests Dr. Ross. Other potential causes of uterus growth can include pregnancy, fibroids (aka tumors that can form either inside or outside the uterus), adenomyosis (when tissue that normally lines the uterus grows into the muscular wall of the uterus), and uterine cancer, she adds.

Bottom line: It's "absolutely important" to know the size and shape of your uterus, as well as the accurate sizing of a normal vs. enlarged uterus, says Dr. Ross. In addition to considering a transvaginal pelvic ultrasound, "it's recommended to get a yearly pelvic exam performed by a trained professional," which "can also give you an idea of whether your uterus is of normal size and shape," she notes.

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