Dysmenorrhoea (menstrual cramps, painful menstruation), involves menstrual periods that are accompanied by either sharp, intermittent pain or dull, aching pain, usually in the pelvis or lower abdomen.

Painful menstruation affects approximately 50% of menstruating women, and 10% are incapacitated for up to 3 days. Painful menstruation is the leading cause of lost time from school and work among women of childbearing age. This pain may precede menstruation by several days or may accompany it, and it usually subsides as menstruation tapers off.

Although some pain during menstruation is normal, excessive pain is not. Dysmenorrhoea refers to menstrual pain severe enough to limit normal activities or require medication. It may coexist with excessively heavy blood loss (menorrhagia).


  • Primary dysmenorrhoea refers to menstrual pain that occurs in otherwise healthy women. This type of pain is not related to any specific problems with the uterus or other pelvic organs.
  • Secondary dysmenorrhoea is menstrual pain that is attributed to some underlying disease process or structural abnormality either within or outside the uterus (for example, pelvic inflammatory disease, fibroids, endometriosis, adhesions, adenomyosis, uterine displacement, or a retroverted uterus). Endometriosis is the most common cause of dysmenorrhoea associated with a disease process and is frequently misdiagnosed.

The incidence of menstrual pain is greatest in women in their late teens and 20s, then declines with age. Some women experience increased menstrual pain in their late 30s and 40s as their endocrine systems prepare for menopause by decreasing hormone levels and thus fertility. It does not appear to be affected by childbearing. An estimated 10 percent to 15 percent of women experience monthly menstrual pain severe enough to prevent normal daily function at school, work, or home.

Risk factors

The majority of women will suffer this degree of disability at least once during their reproductive years. Increased risk is associated with younger age, and past medical history of any of the conditions associated with secondary dysmenorrhoea.

Primary dysmenorrhoea:
- Nulliparity (having never given birth)
- Obesity
- Cigarette smoking
- Positive family history

Secondary dysmenorrhoea:
- Pelvic infection
- Sexually transmitted diseases
- Endometriosis

Primary Dysmenorrhoea

Primary dysmenorrhoea occurs during regular ovulatory cycles. Women with primary dysmenorrhoea have increased activity of the uterine muscle with increased contractility and increased frequency of contractions. Prostaglandins are released during menstruation due to destruction of the endometrial cells and the resultant release of their contents.

Release of prostaglandins and other inflammatory mediators in the uterus (womb) is thought to be a major factor in primary dysmenorrhoea (Wright et al. 2003). Prostaglandin levels have been found to be much higher in women with severe menstrual pain than in women who experience mild or no menstrual pain. Drugs which inhibit the production of prostaglandins, such as the non-steroidal anti-inflammatory drugs (NSAIDs) Naproxen, Ibuprofen and Mefenamic Acid, can provide relief for the discomfort and other associated symptoms of excessive prostaglandin release, such as nausea, vomiting, and headache.

Clinical Features

The cramping associated with dysmenorrhoea usually begins a few hours before the start of bleeding and may continue for a few days. The pain is usually described as being in the lower abdomen, possibly radiating to the thighs and lower back. Other symptoms associated with primary dysmenorrhoea are nausea and vomiting, fatigue, diarrhoea, lower backache, and headache.


Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, are very effective in the treatment of primary dysmenorrhoea. As earlier stated, their effectiveness comes from their ability to inhibit prostaglandin synthesis. However, many NSAIDs can cause gastrointestinal upset as a side effect. Patients who cannot take NSAIDs may be prescribed a cyclo-oxygenase (COX) inhibitor. Oral contraceptives are also sometimes used since they reduce menstrual flow and inhibit ovulation.

Oral contraceptives are second-line therapy unless a woman is also seeking contraception, then they would become first-line therapy. Oral contraceptives are 90% effective in improving primary dysmenorrhoea and work by reducing menstrual blood volume and suppressing ovulation. It may take up to 3 months for the oral contraceptives to become effective. Norplant and Depo-provera are also effective since these methods often induce amenorrhoea.

Secondary Dysmenorrhoea

The mechanisms causing the pain of secondary dysmenorrhoea are varied and may or may not involve prostaglandins. Some causes of secondary dysmenorrhoea are endometriosis, pelvic inflammation, fibroid tumours, adenomyosis, ovarian cysts, and pelvic congestions. The presence of an IUD (intrauterine device) for contraception may also be a potential cause of menstrual pain, although they usually lead to pelvic pain only around the time of insertion. Some women also find that use of tampons exacerbates menstrual cramps and pain.

Clinical Features

The symptoms of secondary dysmenorrhoea vary with the underlying cause, but generally the pain associated with secondary dysmenorrhoea is not limited to the time around menses as with primary dysmenorrhoea. Also, secondary dysmenorrhoea is less related to the onset of bleeding in menstruation, is seen in older women, and is associated with other symptoms like infertility.


The most effective treatment of secondary dysmenorrhoea is the identification and treatment of the underlying cause of the pain, although the relief provided by NSAIDs is often helpful.

The first line of treatment is medical (eg. prostaglandin synthetase inhibitors, hormonal contraception, danazol, progestins). If possible, the underlying disorder or anatomic abnormality is corrected, thus relieving symptoms.

Dilation of a narrow cervical os may give 3 to 6 months of relief (and allows diagnostic curettage if needed). Myomectomy, polypectomy, or dilation and curettage may be required. Interruption of uterine nerves by presacral neurectomy and division of the sacrouterine ligaments may help selected patients. Hypnosis may also be useful.

Endometriosis is a common cause of secondary dysmenorrhoea. In fact, approximately 24% of women who complain of pelvic pain are subsequently found to have endometriosis. This condition is often associated with infertility. If pain relief is the goal, medical options include hormonal contraception, danazol, progestational agents, and GnRH agonists.

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