Period pain… What’s normal?

5 November 2018.

Is your period pain ‘normal’… or a sign of PMS, endometriosis, or fibroids?

Yet again, the silence created by the menstrual taboo has led to unnecessary suffering, and confusion. Let’s bust some myths!

What causes period pain?

First of all, it’s worth noting that there are different types of period pain. [Even ‘normal’ period pain, typically involves two different types; direct (e.g. womb/ uterine cramps), and indirect (e.g. associated pain caused by other menstrual changes)…]

1. Womb or uterine cramps

These are exactly what they sound like; muscle cramps. Only in this case, they are happening for a specific purpose, and not just as a result of older age, over-exercising, or a drop in the body’s salt levels (i.e. like leg cramps) [1].

The womb is largely made up of a thick wall of smooth muscle (the myometrium). This muscle is extremely powerful, and is composed of three layers (in horizontal, vertical and diagonal directions) [2]. Muscle spasms enable important (i.e. critical to the survival of our species) functions of human reproduction: Regularly shaking off old endometrial cells (the inside lining of the womb) as quickly as possible during menstruation, and very occasionally pushing out baby humans during childbirth (known as ‘uterine contractions’).

Cramping is typically described as ‘suddenly intense’ or ‘sharp’ pain, lasting from a few seconds up to several minutes (but not usually any longer than 10 minutes), and tends to come and go in ‘waves’. Cramp pain can begin before the period starts, but it is usually most severe on days 1 and 2 (heavy flow). Technically, period cramps are caused by the destruction of the endometrial cells, and the resulting release of ‘prostaglandins’ [3]. These inflammation response-related chemicals cause the muscle in the womb to contract and spasm [3].

Note– The ‘copper coil’, or non-hormonal IUD (Intrauterine Device), is known to increase the severity of period cramps (and menstrual bleeding) in some people [4]. The cause is not fully understood, but a good quality clinical study found that for most people, this problem resolved between 3 and 6 months of usage [4].

2. Associated period pain

This is more variable in origin and experience. Lower back pain, a feeling of abdominal ‘heaviness’, or an aching vulva (the outside part of female genitals) are the most common forms. This pain is more of a constant ‘ache’ and I personally think that it is similar to ‘toothache’ albeit in a very different location! It certainly creates the same ‘urghhhh’ feeling, and unhappy facial expressions… This type of longer lasting pain is experienced during menstruation, but not usually before bleeding begins. It is usually caused by one or more of a range of menstrual changes; including pelvic muscle/ spine inflammation, water retention, constipation, diarrhoea, or trapped gas.

Back in 2012, the below Facebook post was published (by people who should know better) [5]. Since then it has been shared over a million times, and continues to pop up in menstrual health and sex education forums.

‘Fake news’ caption added by Menstrual Matters. Source: Apples and Ovaries

The post and image claim that there is a visible and significant size difference between a menstruating womb, and a non-menstruating womb. This is absolute nonsense, and yet another example of how profit-making companies don’t care if they spread unhelpful and misleading information about [female] health (so long as it makes them money). Whilst the muscle of the womb does become slightly inflamed during menstruation, there is no noticeable size increase [5]. The ‘heavy feeling’ is simply a form of associated pain, as described above. See this excellent myth-busting blog post by Health Line, for further information…

3. Endometriosis-related pain

This has a different origin to ‘normal’ cramps or associated period pain.

Common locations for endometriosis lesions… Source: Wikimedia

Endometriosis is a condition in which endometrial tissue, the type of cells normally found in the inside of the womb, grow outside it [6]. Typically, the cells form ‘lesions’ (like scar tissue) on the ovariesFallopian tubes, or around the womb, but rarely, they also grow in other parts of the body e.g. the lungs or brain [6].

These cells ‘bleed’ during menstruation and, since the blood has no means of leaving the body cavity, the build up can cause internal inflammation or further lesions [6]. Pain may be experienced as severe ‘cramping’ or ‘stabbing’ pain, anywhere in the abdomen, especially during menstruation, but also as more ‘chronic pain’ (i.e. throughout the entire cycle) [6]. Severe ‘sharp’ pain may also be experienced during sex, or when passing urine or faeces [6], please consult a doctor if you experience any of these symptoms.

Common locations of fibroids. Source: Wikimedia

4. Fibroid-related pain

This also has a different origin to ‘normal’ period pain, although it may feel very much like severe period ‘cramps’. Fibroids are abnormal growths that develop in or around the uterus/ womb. Fibroids are very common, but many people do not know they have them, since they do not experience any symptoms. The size of the growth (a type of benign tumour) makes all the difference; the larger it is, the more likely it will press against the surrounding tissue and organs, causing inflammation and pain.

Fibroid pain is typically worse during menstruation, when it can cause severe period cramps, and heavy bleeding. Pain can also be less severe, but continue throughout the cycle, causing a long lasting feeling of ‘heaviness’, ‘bloating’, or general abdominal discomfort [7].

Normal period pain vs PMS vs endometriosis vs fibroids…

Pain is a subjective symptom, meaning that it is not easily ‘observed’ or ‘detected’ by anyone other than the afflicted person. There is also no way to precisely ‘measure’ pain e.g. through the use of a clinical test. Instead, it is up to the patient to try to accurately describe the severity and type of pain experienced. The best way to do this for period pain, is to track your symptoms! Here is a useful chart with which to ‘score’ your period pain levels (remember to score your short sharp ‘cramp’ pain separately from more constant ‘ache’ pain );

Source: Wong DL, Baker MC, Comparison of Assessment Scale, 1988, Pediatric Nursing; 14; 1-9

Normal period pain– Anything below 5 on the scale, perhaps with occasional ‘bad cramps’ ranging between 5-8 on the scale, but not for longer than 10 minutes at a time or 3 days in a row. You can alleviate period pain through the use of painkillers (especially ibuprofen, so long as you do not have asthma), or even through some simple lifestyle changes.

PMS pain– period cramps and/ or associated period pain in most cycles, severe enough to disrupt daily functioning (5-10). Waking up during the night due to period pain(s). Period cramps might peak high up on the scale, but not for longer than 10 minutes at a time, or for more than 3 days in a row. Associated PMS period pain (abdominal, vulval, leg pain) is more likely to be between 5-8 on the scale, but longer lasting than cramp pain, and during menstruation, only.

Please speak to your doctor, because PMS pain responds well to lifestyle changes/ treatment, and other health issues such as endometriosis or fibroids must also be ruled out, first!

Endometriosis pain– Similar to PMS pain (above), except it might last longer than 3 days in a row, or could occur at times other than just before or during menstruation. Pain may also get worse over time (progressive pain), and is generally linked to lower back or pelvic pain (i.e. not just where the womb is located). You may feel bloated, with some abdominal discomfort, throughout the cycle [6]. Pain during sex, or when passing urine or faeces, can be a sign of endometriosis [6].

Please speak to your doctor, because endometriosis pain can be reduced or even eliminated (through lifestyle changes, the use of painkillers, or hormonal medication that prevents cyclical bleeding altogether), and other health issues such as fibroids must also be ruled out, first!

Fibroids pain– Similar to endometriosis pain (above), but you may also be able to feel a hard mass (lump) inside the abdomen and your periods may be very heavy (over 80ml of fluid per period) [7]. Constipation and/ or diarrhoea are also more likely to occur, throughout the cycle [7]. As with PMS and Endometriosis, please seek medical help as soon as possible, to reduce pain, and prevent the fibroid from getting any larger (if left untreated, fibroids may require surgery) [7].

How to reduce period pain

Even though mild-moderate period pain is ‘normal’, this doesn’t mean that there’s nothing you can do to help reduce it!

Even severe period cramps can be improved by some simple lifestyle changes, and/ or the use of anti-inflammatory painkillers (it’s best to start taking them a couple of days before your period is expected).

The severe pain caused by endometriosis or fibroids, may also be somewhat alleviated in this way, but it is important to seek medical advice because without specific treatment, these issues are likely to get worse over time (until menopause!).

For more detailed advice on what can help reduce, or even stop, period pain- please see our specific symptom management pages on period pain, endometriosis and fibroids.

Citation: King, S. (2018) Period Pain… What’s normal? [ONLINE] Available at: [Accessed- insert date].

References and notes:

Main image at top of page: Peter Southwood (2011) Wikimedia;

[1] NHS (2018) Leg cramps. [ONLINE] Available at: [Accessed 5 November 2018].

[2] Medscape. 2015. Uterus Anatomy. [ONLINE] Available at: [Accessed 5 November 2018].

[3] Lethaby A, Duckitt K, Farquhar C (2013). “Non-steroidal anti-inflammatory drugs for heavy menstrual bleeding”. The Cochrane Database of Systematic Reviews (1): CD000400. doi:10.1002/14651858.CD000400.pub3PMID 23440779

[4] Diedrich, J T. et al. (2014) Association of short-term bleeding and cramping patterns with long-acting reversible contraceptive method satisfaction American Journal of Obstetrics & Gynecology , Volume 212 , Issue 1 , 50.e1 – 50.e8

[5] Here is a great expose of the viral ‘womb inflammation’ photo- well done Healthline!

[6] NIH (2017) Endometriosis overview. [ONLINE] Available at: [Accessed 5 November 2018].

[7] NHS (2018) Fibroids. [ONLINE] Available at: [Accessed 5 November 2018].



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