There is an article in Quartz about period pain (menstrual cramps or dysmenorrhea). While I agree many people, especially doctors, don’t take painful periods seriously enough I disagree with the assertion that we don’t know much about painful cramps. I’m also not a fan of comparing period pain to heart attacks.

Heart attacks are not that painful! Don’t sell period pain so short.

If you are waiting for terrible, excruciating chest pain to tell you that you are having a heart attack, well, you are going to miss the heart attack. Heart attacks often produce vague symptoms or mild pain, that is why many people ignore them. Many people think they are having indigestion. In addition, more than 40% of women have no pain with heart attacks. It would be dangerous for women to think that a heart attack should be at least as bad as their menstrual cramps.

I get that is hard to wrap your brain around the idea that cramps are usually worse than a heart attack. After all the heart muscle is literally dying during a heart attack and the uterus is not dying during a period (although it may feel like that). These facts simply underscore the complexity of visceral pain.

The only similarity between the pain of heart attacks and period cramps is that both the heart and the uterus are innervated by the sympathetic nervous system, which is why the pain is more vague in location or difficult to describe. With heart attacks people typically don’t point to a single spot right over their heart, often it is their arm or jaw or a larger area in their chest. Period cramps are also typically not confined to a single spot, they are usually generalized low back pain or lower abdominal cramps.

What do we know about cramps? It turns out we know a lot!

Primary dysmenorrhea is the term for painful menstrual cramps not due to another cause and so I’m going to limit this discussion to primary dysmenorrhea. About 40-50% of women have primary dysmenorrhea or painful periods; up to 50% of them have severe pain.

The pain of primary dysmenorrhea is mediated mostly by prostaglandins, which are substances involved in the body’s response to inflammation. Prostaglandins are released from the lining of the uterus during menstruation and they cause the uterus to contract. Prostaglandins are also algesic substances, meaning they prime the nervous system for pain (or heighten pain). So prostaglandins have a double whammy effect with period pain, causing painful uterine contractions and an increase in pain signaling. Prostaglandins also bring the joy of nausea, vomiting, and diarrhea that 60% of women get with their periods. Because pain and bleeding just isn’t enough, ya know?

I believe there is no word in any language to describe that unique experience of simultaneously running out of both pads (or tampons) and toilet paper when you are sitting on the toilet and in immediate need of both.

Recent studies tell us that most women with primary dysmenorrhea have increased secretion of menstrual prostaglandin F2 (PGF2) and that menstrual pain seems directly proportional to the amount of prostaglandin F2 that is released. A small percentage of women with severe primary dysmenorrhea do not have increased prostaglandins and so it is hypothesized that they are releasing other inflammatory mediators that cause excessive contractions. It is possible that some women release a normal amount of prostaglandins but have an overly responsive uterus.

Women with painful periods tend to have stronger and abnormal uterine contractions (confirmed by ultrasound in studies). This causes a greater reduction in oxygen delivery and thus more pain.

How strong and abnormal are these contractions?

Glad you asked!

When women have minimal or no cramps the baseline tone of the uterus during their period is less than 10mm Hg; typically there are 3–4 contractions per 10-minute interval and the pressure from a contraction can reach 120 mmHg. This is comparable to the pressure in the uterus during the second stage of labor (i.e. with pushing!). The contractions are regular and coordinated. The contractions help pinch off the blood vessels to reduce bleeding and assist in clotting.

With primary dysmenorrhea several differences have been reported including an elevated basal tone, elevated pressures with contractions (as high as 150 –180 mmHg), an increased number of contractions, and poor coordination of the contractions. These differences result in reduced uterine blood flow with a drop in oxygen delivery increasing pain. When more than one contraction abnormality is present it is believed that they act synergistically to exponentially increase the pain.

There are also studies that suggest some women with severe primary dysmenorrhea may have different pain processing.

So if you need an analogy to describe period pain use labor or cutting your finger off without an anesthetic. A heart attack is often not painful or only mildly painful, especially for women, so for me that analogy just doesn’t cut it.