Published on Aug 12, 2023

6 Minute Read

Why Periods Hurt : A Detailed Scientific Exploration

by Tejas Srivastava

Why Periods Hurt : A Detailed Scientific Exploration


Dysmenorrhea is the medical term for the painful cramps you might experience during your period. The pain can last from a few hours to three days and usually starts on the first or second day of your period. It can feel like a severe ache in your lower belly and can sometimes spread to your back and thighs. You might also feel nauseous, vomit, have diarrhea, feel tired, or have trouble sleeping.

Dysmenorrhea is very common, especially in younger women. About 6 in 10 women experience it after they start getting their periods. Because it's so common, many people think it's just a normal part of having a period and don't seek help for it.

The pain and other symptoms of dysmenorrhea can really disrupt your life. They can make it hard to do your daily activities, affect your performance at work, and even make it hard to socialize. It can also disturb your sleep, making you feel even worse.

Primary and Secondary Dysmenorrhea

Primary dysmenorrhea is when you have menstrual pain but there's no underlying condition causing it. It usually starts a few years after you start getting your periods. 

Secondary dysmenorrhea is when your menstrual pain is caused by a specific medical condition, like Endometriosis or Fibroids. Many times, these underlying diseases are the reason behind severe period pain. 

The most common of such diseases is Endometriosis, where tissue similar to the lining of your uterus grows outside of your uterus. Another cause is Adenomyosis, where this tissue grows into the muscle wall of your uterus.

Other conditions that can cause secondary dysmenorrhea include fibroids (non-cancerous growths in the uterus) and pelvic inflammatory disease (an infection of the female reproductive organs).This type of dysmenorrhea usually starts later (more than two years after your first period) and can come with other symptoms like bleeding between periods.

It's essential for women to consult a healthcare professional if they experience severe menstrual pain, as it could be a sign of secondary dysmenorrhea. Early diagnosis and treatment can help manage the symptoms and prevent potential complications.

Primary dysmenorrhea, while not linked to a specific medical condition, is a complex issue that requires an in-depth exploration.

In the following sections, we'll delve deeper into the fundamentals of our menstrual and ovarian cycle, try to explore the possible causes by considering all the body’s systems, and check out the risk factors and other related issues. We’ll also look at the state of research so far, and tell you about the existing gaps.

Behind the synchronicity of periods : The Female Reproductive system 

Let's first get some of our fundamentals straight. To really understand the issue of period pain, we will need to first know the biology of the female reproductive system.

As you know, the ovaries release a new egg every month that can become a new life. But why every month? What controls this clockwork?

The answer is – the Endocrine system. The endocrine system is the conductor of the orchestra that is your body. It controls and communicates with all the necessary organs through hormones, and keeps the body in symphony.

For our case, let's Imagine this reproductive clock system - the Hypothalamic-Pituitary-Ovarian (HPO) system - as a team of players in a relay race. Here the baton is a message that needs to be passed along to ensure the race - in this case, your menstrual cycle - runs smoothly

The Hypothalamus: This is the starting point of the race. It's a small part of your brain that kicks things off by releasing a hormone called gonadotropin-releasing hormone (GnRH).

The Pituitary Gland: This gland, also in your brain, is the second runner. It receives the GnRH baton from the hypothalamus and responds by producing two hormones: follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

The Ovaries: These are the final runners. They receive the FSH and LH baton from the pituitary gland. FSH encourages your ovaries to mature an egg inside a tiny sac called a follicle, while LH triggers the mature egg's release from the follicle - this is ovulation.

The ovaries also produce estrogen and other hormones that feed back to the hypothalamus and pituitary gland, regulating their activity. This feedback loop ensures that the right hormones are produced at the right time, keeping your menstrual cycle on track.

Once the egg is released, the follicle transforms into a structure called the corpus luteum, which produces progesterone. This hormone prepares the lining of your uterus (the endometrium) for a potential pregnancy. If the egg isn't fertilized, the corpus luteum breaks down, progesterone levels drop, and your menstrual period begins, marking the start of a new cycle. This is the standard state of affairs.

However, if the fertilization (i.e. pregnancy) does happen, then the situation becomes different. The fertilized egg attaches to the uterine wall, and takes over the control of the whole system. The corpus luteum still breaks down, but the egg (now zygote) starts to release hormones Progesterone and Estrogen among others to keep the uterus thick and healthy for the baby.

Prostaglandins - The Pivots behind your Period Pain

Let us come back to the standard menstrual cycle and introduce the last, most important players - Prostaglandins.

Prostaglandins are hormone-like substances that are involved in inflammation, pain, and fever in the body. In the context of menstruation, prostaglandins are responsible for causing the uterus to contract, helping to shed the uterine lining during a period. However, in women with dysmenorrhea, there is an overproduction of prostaglandins, particularly one called PGF2α. This leads to excessive uterine contractions, which can constrict blood vessels and temporarily cut off the supply of oxygen to the uterus.

It's like your uterus is working out too hard without enough oxygen to carry on, and in the process causing something similar to a localized 'heart attack' of the uterus. This is what causes the characteristic pain of dysmenorrhea.

I guess that’s it then. We know an excess of Prostaglandins is the issue. 

What's the rest of the article about then? Fluff? Trying to artificially keep you occupied in this ruthless attention economy? Nope.

If you do a close reading, and maybe take some time to think about the concepts, you’ll realize that we never talked about the reason behind the excess. The reality is, we don’t know what creates this imbalance. We don’t know why it affects only some people sometimes. We just don’t. And that is why so much of the article is still left.

In talking about menstrual pain, we talked about menstruation. But we still have not talked about pain. Perhaps the problem is on that side of the equation?

Defining ‘Pain’

First we need to ask – what is pain? On the surface it is a very dull question. Pain is pain. If somebody doesn’t know, maybe a slap will be an actual educational tool for once.

But the story is actually much deeper and interesting. Pain is like an alarm system in your body. It tells you when something is wrong.The biological process of detecting the problem and sending a signal to your brain is called nociception. The processing of this signal in the brain produces the feeling of pain. Pain is a subjective & emotional experience. It is affected by our mood, attention and even culture. It is complex. Our bodies and brains work together to decide how much something should hurt.

Now, imagine if your brain was a bit too good at its job and started telling you that things hurt more than they should. This is what happens in some girls and women when they have their period. It's like their brain is amping up the volume on the pain, making it feel worse than it might for others. This condition, where the uterine contractions are not special but instead the threshold of pain is lower, may be the cause of period pain.

Sometimes, this ‘volume increase’ doesn't just happen during their period, but at other times too, making them feel pain more intensely in general. Its like having your TV volume set so high that even the quiet parts of the movie become really loud. This is what the term "central sensitization" means - the brain's volume control for pain is stuck on high.

So, women with primary dysmenorrhea don't just have painful periods, they might also experience other types of pain more intensely. It's like their brain is ready to tell them that something hurts a lot, even when it shouldn't be that painful.

So is this the answer? Instead of going on another tirade, let me just tell you – No it is not. As before, we don’t really know why the peculiar phenomenon of lower pain thresholds exists. Is this merely a byproduct of dysmenorrhea, or an after-effect? 

There is just a lot of stuff going on in our bodies.There are tons and tons of systems that are all interconnected. The part of the female anatomy responsible for the miracle of creating life, surely couldn't have been that simple to decode.

The difficulties in solving this mystery isn’t just due to purely medical reasons. While we have come a long way both in our understanding of the world and as a society, the ugly head of gender bias still rears its head.

Gender bias and other risk factors in the study of Menstrual Pain

When scientists conduct medical research, they often use mostly men in their studies. This is what we call 'gender blindness'. Even though people have been criticizing this approach since the 1970s, it's still happening. The result is that we end up with medical advice and treatments that are based mostly on men's bodies, which might not work the same for women.

This bias can sneak into the subjects of medical research and healthcare as well, leading to less focus on women's health issues. A good example is that menstrual pain is often seen as 'normal' or 'not a big deal', so it doesn't get the attention and resources it needs for better understanding and treatment.

From statistical studies on large groups of women, we have observed the characteristics or conditions that increase the likelihood of developing primary dysmenorrhea. Such characteristics are called Risk factors. They can be environmental, behavioral, physiological, genetic, or even social. (For example, smoking is a risk factor for lung cancer.) Risk factors matter because they help us understand the causes of diseases and injuries. Also by identifying risk factors, we can take steps to reduce our risk. (For example, we can reduce our risk of lung cancer by not smoking).

Risk Factors -

Age - Younger women, especially those under 30, are more likely to experience dysmenorrhea. As you age, the severity of dysmenorrhea often decreases. So, if you're a young woman experiencing menstrual pain, it's not uncommon and it may lessen as you get older.

Family History - If your mother or sister have experienced dysmenorrhea, you're more likely to experience it. However, this doesn't mean you will definitely experience it. It's just something to be aware of, and perhaps discuss with your healthcare provider if you're concerned.

Stress - High levels of stress can increase the risk of dysmenorrhea. This means that if you're experiencing high levels of stress at work or in your personal life, it could contribute to menstrual pain. Techniques like yoga, meditation, or talking to a mental health professional might be beneficial.

Parity and Oral Contraceptive Use - Women who have given birth or use oral contraceptives are less likely to experience dysmenorrhea. This doesn't mean you should rush to have a child or start using oral contraceptives, but it's a factor to discuss with your healthcare provider when considering your overall reproductive health.

Smoking - Some studies suggest that smoking may increase the risk of dysmenorrhea. If you're a smoker, this is another health reason to consider quitting.

Diet - A healthy diet may help manage dysmenorrhea symptoms. Maintaining a balanced diet with plenty of fruits, vegetables, lean proteins, and whole grains might help. Some women find that reducing caffeine and sugar intake can also help.

Obesity - Being overweight may increase the risk of dysmenorrhea. Regular exercise and a healthy diet can help maintain a healthy weight, which might reduce dysmenorrhea symptoms.

Depression and Abuse - These factors can increase stress levels, which may in turn increase the risk of dysmenorrhea. If you're dealing with depression or any form of abuse, please seek help from a healthcare provider or support organization.

A scientifically positive outlook in the field of Menstrual relief

Studying primary dysmenorrhea and testing new treatments presents a unique challenge for scientists. As you would have understood by now, primary dysmenorrhea is a complex process. Scientists first need a reliable model of the condition - Models provide a controlled environment to study diseases and test treatments, ensuring their safety and effectiveness.

Recently, several advances have been made towards reliably modeling the vast system. We present to you three of them:

In-silico organ models - Scientists have created a miniature version of the female reproductive system in the lab. This "lab-on-a-chip" model is designed to mimic the natural hormonal cycles of the female body, including the menstrual cycle. This is a significant advancement because it allows researchers to study the female reproductive system in a controlled environment, which was previously a challenging task.

Mathematical models – Mathematical modeling (Simulation of the system in a computer by deriving and solving mathematical equations) has been a significant tool in understanding the complex processes of the menstrual cycle. Over the past decade, several mathematical models have been developed, each focusing on different aspects of the hypothalamic-pituitary-ovarian (HPO) system. Many other branches of research these days fundamentally rely on such mathematical studies for their own work. 

Animal models - Animal models, particularly mice, are very important in research. Mice are mammals just like humans, and their internal organs not only provide a decent similarity to human beings – they are also much easier to study in controlled situations.

In one study, researchers induced recurrent primary dysmenorrhea in mice using estrogen and oxytocin. This model successfully replicated the clinical features of the condition over two cycles, offering a valuable resource for further research.

Despite there being a long way to go, the daily struggles faced by millions of individuals going through menstrual pain has not gone unnoticed. Scientists, medical professionals and social reformers continue to pave way for transformative breakthroughs for hope to bloom for a menstrual-pain free possibility.