Dysmenorrhoea

Dysmenorrhoea is a term used to describe low anterior pelvic pain which occurs in association with periods.

Pathogenesis¹

It is thought to be due to an excess or imbalance of prostaglandins and leukotrienes in the menstrual fluid, which in turn produces vasoconstriction in the uterine vessels, causing the uterine contractions which produce the pain. The prostaglandin release may also be responsible for the symptoms of diarrhoea, nausea, headache and light-headedness which may occur in association with dysmenorrhoea.

Classification

Dysmenorrhoea may be thought of as either primary or secondary.

Primary dysmenorrhoea

Primary dysmenorrhoea occurs in young females with no pelvic pathology.

• It often begins with the onset of ovulatory cycles six months to one year after the menarche² .

• The pain begins with the onset of the period and may last for 24-72 hours.

Secondary dysmenorrhoea

Secondary dysmenorrhoea occurs in association with some form of pelvic pathology:

• It is more likely to occur years after onset of menstruation.

• The pain can precede the start of the period by several days and may last throughout the period.

• There may be associated dyspareunia.

• Secondary dysmenorrhoea may occur as a result of:
  

  • Endometriosis/adenomyosis.

  • Pelvic inflammatory disease.

  • Fibroids, when it is often associated with heavy menstrual bleeding.

  • Adhesions.

  • Developmental abnormalities.

  • The copper-containing intrauterine contraception device (Cu-IUCD) may cause pelvic pain in the first few months after fitting but does not influence the severity of dysmenorrhoea in the longer term³ .

Epidemiology

• Dysmenorrhoea is common. Prevalence rates vary widely and range from 16-91% in women of reproductive age, with severe pain reported in 2-29% of women⁴ .

• Longer duration of menses, early menarche, smoking, alcohol and obesity are all risk factors associated with dysmenorrhoea² .

• Childbirth reduces dysmenorrhoea and its severity diminishes with age³ .

Assessment⁵

A presumptive diagnosis of primary dysmenorrhoea may be made on history ± abdominal examination alone in young patients who are not sexually active, and vaginal examination is not normally required in this group of patients.

Investigation of dysmenorrhoea is primarily aimed at ruling out underlying pathology and may include any or all of the following as appropriate to the individual.

History

• Age at menarche.

• Cycle length.

• Whether the cycle is regular.

• Duration of bleeding.

• Timing of pain in relation to period.

• Location of pain. Dysmenorrhoea is typically suprapubic but may be felt in the back of the legs or lower back

• Smoking history.

• Whether the patient is sexually active.

• Obstetric history.

• Contraceptive history.

• Any features suggestive of underlying pathology (eg, vaginal discharge, intermenstrual or postcoital bleeding, dyspareunia).

• Dyschezia and/or rectal pain or bleeding - particularly suggestive of endometriosis.

Examination

Abdominal/vaginal examinations are indicated if sexually active:

• Adenomyosis - the uterus may be enlarged and tender with a typical 'boggy' feel.

• Endometriosis - generalised tenderness in the pelvic area. The uterus may be fixed ± retroverted due to adhesions, and nodules may be palpable in the uterosacral ligaments.

• Partially imperforate hymen (rare).

• Vaginal septum (rare).

Additional investigations

• Speculum examination to visualise the cervix.

• High vaginal swab, chlamydial swabs.

• Cervical smear, if due.

• Pelvic ultrasound - if uterine enlargement or adnexal mass is present.

• Transvaginal ultrasound.

Specialist investigations

• MRI scan.

• Laparoscopy.

• Laparotomy with biopsy.

Management

General measures

Patients may be concerned about the possibility of underlying pathology and, when appropriate, reassurance and an explanation of the mechanism of menstrual pain may be helpful.

• Lifestyle changes - longitudinal studies have looked at risk factors for dysmenorrhoea and have found a clear association between smoking and dysmenorrhoea; patients should therefore be informed of this relationship and assisted in any attempts to stop smoking⁶ .

• There is low-quality evidence that exercise, performed for about 45 to 60 minutes each time, three times per week or more, regardless of intensity, may provide a clinically significant reduction in menstrual pain intensity⁷ .

• Self-help techniques:
  

  • There is some evidence for benefit from transcutaneous electrical nerve stimulation (TENS) use (high-frequency) and locally applied heat⁴ .

  • Anecdotally, many women find the following measures to be helpful in relieving the symptoms of dysmenorrhoea:
    

    • Tea - regular, camomile or mint.

    • Abdominal and/or back massage.

    • Lying in the supine position.

• Complementary and alternative medicines - several dietary supplements and herbal remedies have been suggested but there is insufficient evidence to recommend any of them⁵ . They include calcium and magnesium, thiamine, ginger, fish oil supplements, toki-shakuyaku-san (TSS - a Japanese herbal remedy), acupuncture and acupressure. Some remedies may have adverse effects and may interact with medication.

Pharmacological

• NSAIDs appear to be a very effective treatment for dysmenorrhoea. However there is a significant risk of adverse effects⁸ .

• Ibuprofen is most often used due to its low incidence of side-effects. Although licensed specifically for dysmenorrhoea, there are concerns that mefenamic acid is more likely to induce seizures in overdose and has a low therapeutic window increasing the risk of accidental overdose⁴ .

• Weak opioids - there is no evidence of beneficial effect and the potential for addiction means they are not recommended.

Hormonal treatments
If the woman with dysmenorrhoea does not wish to conceive, offer her hormonal contraception. Ovarian suppression appears to control cyclical pelvic pain, whether or not caused by endometriosis. Adolescents and young adults who do not respond to hormonal treatment after three months should be evaluated for secondary causes of dysmenorrhoea⁹ . This is likely in approximately 10% of patients.

• Combined hormonal contraception (CHC) is often used¹⁰ . Despite the common use of oral CHC in the treatment of dysmenorrhoea (and guidance from the Faculty of Sexual and Reproductive Healthcare stating it can be used for this purpose from the menarche¹¹ ), previous evidence has been inconclusive, due to a lack of randomised controlled trials . However, CHC can also be used to increase cycle length by tricycling and hence reduce the frequency of the menses and therefore the symptoms⁴ .

• Oral progestogen-only contraception may also be used. In a study of 406 women with dysmenorrhoea who were given desogestrel 75 micrograms/day (Cerazette^®), the pain resolved or improved considerably in 93% and, despite a high incidence of adverse effects, mainly bleeding irregularities, 90% were satisfied¹² .

• Depo-medroxyprogesterone acetate (Depo-Provera^®) is also sometimes used, as many women become amenorrhoeic within a year of starting treatment.

• The levonorgestrel-containing intrauterine system (LNG-IUS; Mirena^®) has been shown to reduce the severity of dysmenorrhoea despite not being anovulatory³ It could also be considered, even in adolescents¹³ . Neither the 52 mg LNG-IUS (Mirena^®) nor the newer 13.5 mg LNG-IUS (Jaydess^®) is licensed for the treatment of dysmenorrhoea; Jaydess^® is less likely than Mirena® to lead to amenorrhoea¹⁴ .

• Danazol is rarely used now and only under specialist supervision in the treatment of severe refractory cases.

• Leuprolide acetate may be used in rare cases to suppress the menstrual cycle, but has a significant side-effect profile.

Surgery

• Laparoscopic uterine nerve ablation (LUNA) has been used for the treatment of severe refractory cases; however, a Cochrane meta-analysis concluded that there is insufficient evidence of its effectiveness and it is not recommended^{15 16} .

• Hysterectomy. In severe refractory cases, particularly in women who feel they have completed their families, hysterectomy may be considered.