FACT:  False.

Experts say the uterus does not change size during menstruation. Bloating and heaviness are caused by hormonal fluctuations and water retention.

You’ve probably noticed that your body feels heavier and more bloated when your period arrives—even if your diet or exercise routine hasn’t changed. But is your uterus really expanding during this time?

That’s the question raised by Emmie Keefe, better known as Healthy Emmie, a nutritionist and weight loss specialist with over 764,000 Instagram followers, whose recent viral reel has left viewers intrigued.

According to her LinkedIn profile, she “has been featured in Forbes, Business Insider, HuffPost, and Apple News+, with over one million followers across her social media accounts.” She describes herself as a nutritionist and weight loss specialist who has built “a team of dietitians, doctors, therapists, coaches, and the like, to work directly with clients to support them on their weight loss journey.”

In the reel, Keefe uses two fruits to make her case. Holding up a plum, she says, “This is your uterus. It weighs about two ounces (56.7g).” Then, switching to a grapefruit, she adds, “This is your uterus on your period. It weighs about eight ounces (226.7g).”

Her caption reads, “It (uterus) can quadruple in weight and expand in volume up to 10–15 pc. And, you’re holding onto about five pounds (2.27 litres) of water weight due to hormonal fluctuations. So yeah, it’s the perfect storm.”

Her takeaway is: if your uterus is carrying four times its normal weight during menstruation, it’s only natural to feel heavier and bloated. She also advises her ‘Slim program’ clients not to weigh themselves during this time and to opt for comfier clothing instead.

The reel has already attracted over 5 lakh views, sparking widespread curiosity and debate. But it also raises an important question: Does the uterus really expand that much during periods?

Does the uterus expand during periods? 

A 1975 study measured changes in the size of the non-pregnant uterus using B-scan ultrasonography in 16 women with confirmed ovulatory cycles. It concluded that the uterus grows significantly toward the end of the menstrual cycle, which is essentially right before your period starts.

However, later studies, done with MRIs and larger samples, have shed more light and shown that what increases is endometrial thickness, rather than uterine size. For instance, a  2007 study that looked at the MRIs from 100 women said, “When we compared the volume of the uterus and cervix and the thickness of the uterine wall layers between the two phases of the menstrual cycle, we found no significant differences.”

This seems to be the modern medical consensus too.  Dr Mansi Sharma, consultant obstetrician and gynaecologist at Motherhood Hospitals, Pune, explained that the uterus is a muscular organ, primarily made of the myometrium. She clarified, “During menstruation, the size of the uterus, as such, doesn’t change. The size of the uterus does change during pregnancy, but not during menstruation.”

Referring to the viral reel suggesting the uterus quadruples in size, she said, “That is not correct, because there is no change in the muscle mass as such to make it four times its actual size.”

Dr Sharma noted that sensations like heaviness, bloating, and breast tenderness are due to hormonal fluctuations and water retention. “These changes – swelling over the face, overall body bloating, breast tenderness, lethargy, mood swings are related to overall body changes, not to the uterus musculature itself,” she explained.

She added that overall body weight can fluctuate during menstruation due to water and salt retention. “If you weigh yourself during your period, you may notice an increase, but that’s due to overall water retention, not a change in the size of the uterus,” she said.

This was seen in a 2023 study from Greece, where researchers found “an increase of approximately 0.5kg was observed during women’s menstrual cycle, mostly due to extracellular fluid retention on menstruation days.”

Dr Sharma also added that “these physiological changes (bloating, breast tenderness, mood swings) are hormonally driven and a normal part of the menstrual cycle.”