What are the underlying causes of period cramps?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Period cramps are primarily caused by prostaglandins, hormone-like substances that trigger the uterus to contract in order to shed its lining. Higher levels of prostaglandins are linked to more intense contractions, which reduce blood flow and oxygen to the uterine muscle, resulting in the pain and discomfort many people experience during menstruation.

While cramps are common, severe or persistent pain isn't something you should simply endure—it can sometimes signal underlying conditions like endometriosis, fibroids, or pelvic inflammatory disease. Understanding your symptoms is the first step toward relief and proper care. Take a free, instant, online symptom check to better understand what may be causing your cramps and get personalized guidance on your next steps.

Reviewed for medical accuracy: 07/14/2026

Important Next Steps

Learn what causes period cramps Discover if cramps need medical care See if pain could be serious Find OTC relief for menstrual cramps Find doctors for severe period cramps Understand home remedies for period pain Check likely causes of your cramps

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Explanation

Period cramps, also known as dysmenorrhea, are caused by the natural process in the body during menstruation. The main culprit behind the cramps is a group of chemicals called prostaglandins.

What are Prostaglandins?

Prostaglandins are chemicals made by the body that help the uterus contract.
These contractions help shed the lining of the uterus, which is what happens during a period.
Sometimes, these contractions can be very strong, leading to painful cramps.

Other Factors:

Some people might have more prostaglandins, which can cause more pain.
The exact reason why some people have more painful cramps than others is not completely understood.

Understanding these causes can help in managing and relieving the pain associated with period cramps. Remember, if you have concerns about your menstrual health, you can use a free symptom checker to better understand your symptoms or talk to a healthcare professional.

(References)

Rosenwaks Z, & Seegar-Jones G. (1980). Menstrual pain: its origin and pathogenesis. The Journal of reproductive medicine, 7001019.
Deligeoroglou E. (2000). Dysmenorrhea. Annals of the New York Academy of Sciences, 10818411.
Friederich MA. (1983). Dysmenorrhea. Women & health, 6685410.

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