Reviewed February 2021

Telltale signs your period pain is secondary dysmenorrhea

Three women standing next to each other

We’ve all had it. The dull ache in your lower stomach, sometimes just there, at other times peaking and leaving you in bed clutching a hot water bottle. The medical term for period pain is dysmenorrhea. It is common, and is estimated to affect up to 90% of those who menstruate.1 Period pain can affect daily activities such as school or work.

Period pain can be separated into two types: primary or secondary dysmenorrhea. The former is when the period pain occurs without an underlying condition causing it and the latter is when there is a known cause, such as uterine fibroids (benign growths in the womb lining) or endometriosis (where womb tissue is found outside of the uterus).

Primary dysmenorrhea occurs because the body makes chemicals called prostaglandins, which cause the uterus to contract during menstruation in order to shed the lining. Sometimes the pressure in the womb caused by this contraction is more than the pressure in the blood vessels supplying the womb, which leads them to collapse. This restricts blood flow to the womb, leading to the release of other chemicals that stimulate your pain nerves, which results in painful periods.2,3

Primary dysmenorrhea occurs without an underlying condition causing it, whereas secondary dysmenorrhea has a known cause

Primary dysmenorrhea generally starts in puberty when periods first start. It occurs one or two days before bleeding commences, and then slowly gets better over the next 12 to 72 hours. It occurs with most, if not all, periods. The pain has been described as “crampy” or “a constant dull ache”, or some say that “it comes and goes”. It is felt in the lower tummy over the bladder, with the pain strongest in the middle. Some people may also get pain in their back or down their thighs.

Primary dysmenorrhea can range from being mild to extremely severe, and in some cases can even cause fainting because the pain is so bad.4 But the severity of the pain is not an indicator of whether or not your dysmenorrhea is primary or secondary; it can be mild or severe in secondary dysmenorrhea too.

Treatment for primary dysmenorrhea depends on the affect your pain is having on your daily life. Non-medical treatments include the aforementioned hot water bottle, exercise, and relaxation therapy such as yoga or meditation. Medications, such as Ibuprofen can be used, and the contraception pill can also be used to affect your periods and thus the pain that comes with them.

Signs of secondary dysmenorrhea

One of the telltale signs that your dysmenorrhea may be secondary rather than primary is inadequate relief of pain even after three months of treatment with medications such as painkillers or the pill.

Alternatively, you may not previously have had period pain, but have noticed it occurring since the age of around 25 years.

In general, as stated above, period pain occurs at puberty, so to have it presenting later in life may be related to another condition. This is not a solid indicator, however, as occasionally conditions such as endometriosis can develop in teenagers. Further evidence that your pain may be secondary include abnormal menstrual bleeding, such as heavy periods, unusually light periods, bleeding after sexual intercourse, or bleeding between periods.

One of the telltale signs that your dysmenorrhea may be secondary rather than primary is inadequate relief of pain after three months of treatment

When period pain occurs either on the left or the right side of the pelvis rather than in the middle it can indicate conditions such as endometriosis and fibroids. On top of this, if your pain seems to worsen over 72 hours rather than improving, it can be an indication your pain is related to a condition rather than simply being period pain. Other unusual symptoms which could point to a secondary condition include smelly or coloured vaginal discharge, pain on passing urine, having a fever, or having chills.

Which conditions cause secondary dysmenorrhea?

There are a wide variety of conditions that can cause secondary dysmenorrhea. Pelvic inflammatory disease (PID), for example, is an inflammation of the reproductive tract, often caused by an infection. It can present like primary dysmenorrhea in that it can cause period pain in the lower tummy that can be mild to severe. The inflammation caused by PID releases chemicals that stimulate pain nerves, thus causing the pelvic pain.

However, unlike in primary dysmenorrhea, the pain is generally in the left and right hand sides of the pelvis and may worsen with sex, which is unusual for primary dysmenorrhea. Other symptoms include abnormal menstrual bleeding (light or heavy periods), smelly or coloured vaginal discharge, and fever or pain on passing urine. These symptoms do not occur in primary dysmenorrhea.


Endometriosis is one of the most common causes of secondary dysmenorrhea. Like primary dysmenorrhea, the pelvic pain can happen at the time of menstruation, but it can also occur at other times not related to periods. The pelvic pain can be so bad as to lead to days missed at work or school.

There is some overlap in the symptoms between the different conditions that can cause secondary dysmenorrhea. For example, adenomyosis and fibroids can both cause pelvic pain outside of menstruation

Symptoms suggestive of endometriosis include pain on sexual intercourse, period pain that does not improve upon taking anti-inflammatory medication like ibuprofen, and the worsening of pains during menstruation as opposed to gradual improvement.

Endometriosis causes pain because there are an increased amount of chemicals produced due to the inflammation, which stimulates pain nerves, as well as an increase in the number of pain nerve fibres, which are stimulated more easily.5,6,7


Adenomyosis is a condition where the womb tissue grows into the uterine muscle layer, and it can cause pain during menstruation because an increased amount of pain nerves are stimulated when the womb muscles contract during menstruation.8,9 However, with adenomyosis the period pain doesn’t usually start until after the age of 35 years and the pelvic pain can also occur at other times outside of menstruation.


Fibroids, benign growths in the womb, are another common cause of secondary dysmenorrhea. The discomfort can be mild or severe, depending on how big and where the benign growths are. The fibroid may stretch the uterus, stimulating the pain nerves and causing pain. Unlike primary dysmenorrhea, pelvic pain with fibroids is most common after the age of 25 years, and it can occur outside of your period, or during sex. Heavy menstrual bleeding is also common with fibroids.

When to see your doctor

There is some overlap in the symptoms between the different conditions that can cause secondary dysmenorrhea. For example, adenomyosis and fibroids can both cause pelvic pain outside of menstruation, and both can cause pain in the lower tummy.

However, telltale signs of secondary dysmenorrhea include period pain not improving after several months of treatment, pain occurring more to one or both sides rather than in the middle of the pelvis, pain starting after the age of 25, abnormal menstrual bleeding, pain on sexual intercourse, pain worsening during the course of menstruation, and any other symptoms not associated with periods, such as fever or abnormal vaginal discharge. If you experience any of these symptoms, it could be an indication that it is not just “normal” period pain, and you should see your GP for investigation.

Your GP will then take a medical history from you to decide whether primary or secondary dysmenorrhea is more likely. You may find it useful to keep a symptom diary to explain to your GP the timings of the pain and where it occurs in your abdomen. Sometimes, fibroids may be large enough for the doctor to spot upon feeling the tummy. If your GP suspects PID they may perform blood tests to look for inflammation. An ultrasound scan may be requested by your GP to look for conditions such as fibroids. Depending on the individual circumstances, symptoms and effect on daily life, your GP may refer you to a gynaecologist for further investigation and treatment.
Featured image is of three women standing against the wall, and is cropped in a way to make with their pelvic areas the focus of the frame. There is a red, gradient overlay over the image

Last updated February 2021
Next update due 2024

Dr. Diana Chiu, MBChB (Hons) MRCP PGCERT (Med Ed) PhD

Diana received her medical degree, with honours, from the University of Manchester. She then went on to receive basic and specialist medical training within the north west of England. She carried out in-depth research in medicine and was awarded a PhD in 2016. Currently, she is finishing her medical training at a large teaching hospital, and one of her greatest interests is medical education. She is an advanced life support instructor and writes regularly for post-graduate examination websites, and also holds a PGCERT in medical education with distinction.

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  1. Ju, H., et al., The prevalence and risk factors of dysmenorrhea, Epidemiologic Reviews, 2014, vol 36, issue 1, pp 104-113
  2. Chan, W. Y. et al., Relief of dysmenorrhea with the prostaglandin synthetase inhibitor ibuprofen: effect on prostaglandin levels in menstrual fluid, American Journal of Obstetrics and Gynaecology, Vol. 135, No. 1, 1979, 102-8.
  3. Altunyurt, S., et al., Primary dysmenorrhea and uterine blood flow: a color Doppler study, Journal of Reproductive Medicine, Vol. 50, No. 4, 2005, 251-5.
  4. Fang, L., Metabolomics study on primary dysmenorrhea patients during the luteal regression stage based on ultra performance liquid chromatography couples with quadrupole-time-of-flight mass spectrometry, Molecular Medicine Reports, January 2017, pp 1043-1050 [online] (accessed 28 February 2021)
  5. Wang, G.,  et al., Rich innervation of deep infiltrating endometriosis, Human Reproduction, Vol. 24, No. 4, 2009; 827-34.
  6. Tran L. V., et al., Macrophages and nerve fibres in peritoneal endometriosis, Human Reproduction, Vol. 24, No., 4, 2009; 835-41.
  7. Mckinnon, B. D.,  et al., Inflammation and nerve fiber interaction in endometriotic painTrends in Endocrinology and Metabolism, Vol. 26, No. 1,  2015; 1-10.
  8. Mao, X., et al., The retardation of myometrial infiltration, reduction of uterine contractility, and alleviation of generalized hyperalgesia in mice with induced adenomyosis by levo-tetrahydropalmatine (l-THP) and andrographolide, Reproductive Sciences, Vol. 18, No. 10, 2011, 1025–1037.
  9. Guo, S. W., et al., Dysmenorrhea and its severity are associated with increased uterine contractility and overexpression of oxytocin receptor (OTR) in women with symptomatic adenomyosisFertility and Sterility, Vol. 99, No. 1, 2013, 231–240.

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