Dysmenorrhea

Dysmenorrhea is pain — typically crampy, lower mid-abdominal and/or pelvic pain — occurring with menstruation. Primary dysmenorrhea occurs without identifiable pelvic pathology, in ovulatory cycles, and results from excess endometrial prostaglandin production driving painful myometrial contractions and transient uterine ischemia; onset is usually within 2 years of menarche, it is most severe in young nulliparous patients, and it tends to improve with age. Secondary dysmenorrhea results from an identifiable underlying pelvic pathology — most often endometriosis, adenomyosis, or a structural/obstructive uterine abnormality — and its age of onset is variable.^[1] Dysmenorrhea is common and frequently undertreated despite effective, low-cost therapy being available. A therapeutic trial of an NSAID and/or hormonal contraception should be started on the strength of a typical history, without waiting for a pelvic examination or imaging, whenever the presentation is a classic primary-dysmenorrhea pattern.

Typical pattern of primary dysmenorrhea

Pain classically starts within several hours before the onset of menstrual bleeding, up to a few hours after the start of menses, and lasts a maximum of about 3 days. It is described as crampy, cyclic, lower mid-abdominal and/or pelvic pain that may radiate to the back or thighs.

Because the pain is driven by systemic prostaglandin release, it is frequently accompanied by other prostaglandin-excess symptoms: nausea, vomiting, diarrhea, backache, thigh pain, headache, and dizziness.^[1]

• Menarche before age 12.
• Increased duration and volume of menstrual flow.
• Smoking or passive smoke exposure — an independent risk factor for dysmenorrhea.
• Low body mass index.
• Family history of dysmenorrhea.
• Nulliparity.
• Mood disorders.
• Prior sexual abuse.
• Poor social support.

History

Take a thorough history of the pain's severity, timing, duration, and character, along with aggravating and relieving factors. The pain of primary dysmenorrhea typically starts within several hours before the onset of bleeding up to a few hours after the start of menses, lasts a maximum of 3 days, and is described as crampy, lower mid-abdominal and/or pelvic pain, often with nausea, vomiting, diarrhea, backache, thigh pain, headache, or dizziness.^[1]

Physical examination

Examine the abdomen and pelvis to look for signs of secondary dysmenorrhea. In a patient who has never been sexually active, an abdominal examination and inspection of the external genitalia are sufficient. In a sexually active patient, add a single-digit vaginal examination, carefully palpating each pelvic structure to isolate tenderness, masses, or nodules. Suspect secondary dysmenorrhea specifically in a patient over age 30 with no prior history of dysmenorrhea, and in any patient refractory to first-line medical therapy.

Investigations

No laboratory test is required or helpful for diagnosing primary dysmenorrhea. In the absence of an abnormal history or examination finding, diagnostic imaging is unlikely to help and may mislead if it turns up a noncontributory incidental finding.

Reserve diagnostic laparoscopy for refractory dysmenorrhea in which endometriosis is suspected — this is a specialist-directed investigation, not a routine primary-care step.^[1]

Primary vs. secondary dysmenorrhea: distinguishing features

• Decrease or abolish menstrual pain and the associated prostaglandin-excess symptoms.
• Restore normal activity, attendance, and quality of life during menses.
• Avoid unnecessarily delaying symptomatic treatment while a definitive diagnosis is pursued.
• When contraception is also desired, select a therapy that accomplishes both goals at once.
• For secondary dysmenorrhea, identify and direct treatment at the specific underlying cause.

• Heat therapy (a heating pad or heat patch applied to the lower abdomen) achieves analgesic efficacy comparable to an NSAID with substantially fewer adverse effects, though the certainty of the pain-reduction evidence is still rated low to moderate — a reasonable option, particularly for a patient who cannot or prefers not to use conventional pharmacotherapy.^[3]
• Regular exercise may provide pain relief. Both low-intensity (e.g., yoga, stretching) and high-intensity (e.g., aerobic training) exercise for 45–60 minutes, 3 times per week, have shown benefit; in most supporting studies, exercise was carried out throughout the month, including during menses.^[4]
• High-frequency transcutaneous electrical nerve stimulation (TENS) reduces pain and reduces the need for additional pain medication compared with placebo, based on moderate-quality evidence.^[5]
• Smoking cessation — smoking is an independent risk factor for dysmenorrhea; support cessation as part of ongoing management.
• Natural health products — evidence quality is generally low across this category, but several may provide benefit: fenugreek, ginger, valerian, zataria, zinc sulphate, fish oil, fish oil plus vitamin B1, and vitamin B1 alone.^[6] Ginger has the most supportive data specifically: 750–2000 mg PO daily for 3–4 days, starting at the onset of the menstrual cycle.
• Surgical management (laparoscopic uterosacral ligament resection, presacral neurectomy, or hysterectomy with or without oophorectomy) is reserved for dysmenorrhea refractory to medical management, usually in the context of secondary dysmenorrhea.
• Current evidence for behavioural interventions and acupoint stimulation (acupressure or acupuncture) remains limited and does not support a specific recommendation over the measures above.

Pregnancy

Dysmenorrhea occurs with ovulatory menstrual cycles and does not apply during pregnancy. For a patient trying to conceive, avoid relying on an NSAID for cycle-related pain around the expected time of ovulation or implantation, and use acetaminophen instead if analgesia is needed; NSAIDs and combined hormonal contraceptives are not appropriate once pregnancy is confirmed or suspected.

Breastfeeding

Ibuprofen and naproxen are both considered compatible with breastfeeding at usual analgesic doses. Combined hormonal contraceptives are generally avoided in the first 6 weeks postpartum and used with caution while breastfeeding is being established thereafter; a progestin-only option (the LNG-IUS, DMPA, or the etonogestrel implant) is preferred if a breastfeeding patient needs hormonal management of dysmenorrhea.

Adolescents

NSAID and combined hormonal contraceptive therapy are both appropriate first-line options in adolescents, and treatment can be started on the strength of a typical history without requiring a pelvic examination first.^[7] Consider a congenital Müllerian anomaly (e.g., an obstructive outflow abnormality) in an adolescent with severe dysmenorrhea dating from menarche, particularly if it is refractory to first-line therapy.

Adolescents 12-18 years using DMPA

Use DMPA with caution in this age group, since peak bone mass has not yet been reached; bone mineral density typically returns to baseline after discontinuation. Encourage adequate calcium (1200 mg elemental calcium daily from all sources, preferably dietary) and vitamin D (1000 units daily) while on DMPA.

Renal impairment

Avoid NSAIDs in severe renal impairment; use the lowest effective dose for the shortest duration, with caution, in milder renal impairment.

NSAID or ASA hypersensitivity

Celecoxib may be considered in a patient with NSAID hypersensitivity, including ASA-hypersensitivity, depending on the specific type of reaction — assess the reaction pattern before selecting an alternative agent, and avoid celecoxib specifically in a patient with a sulfonamide allergy.

Reassess response after a therapeutic trial of 3-6 months with either an NSAID (regularly scheduled, starting before or at the onset of menstruation, continued 2-3 days) or a combined hormonal contraceptive — this duration is usually sufficient to judge effectiveness. At each follow-up, confirm the medication is actually being taken on a fixed schedule starting early enough in the cycle, not as a late PRN dose once pain is already severe. With regular NSAID use, ask about GI symptoms (dyspepsia, black stool) and reassess the ongoing need versus risk, particularly with continued long-term use. For a patient using DMPA, review bone-health counselling (calcium/vitamin D) and the trade-off of delayed return to fertility at each visit. If pain is not controlled at 3-6 months despite an adequate, correctly-taken trial, proceed to the Treatment Failure/Next Step sequence rather than simply repeating or increasing the same regimen.

1. Confirm the regimen was actually taken correctly — the right drug, an adequate loading dose, a fixed (not PRN) schedule, and started at or just before the onset of symptoms or menses rather than after pain was already established.
2. If an NSAID alone has been tried and is inadequate, add or switch to a combined hormonal contraceptive (or vice versa) — this combination is reasonable even though no trial has directly tested it.
3. If estrogen-containing therapy is contraindicated or unwanted, try a progestin-only option (the LNG-IUS, DMPA, or the etonogestrel implant) instead.
4. If pain remains refractory despite an adequate combination trial, proceed to investigation for secondary dysmenorrhea: a pelvic examination if not already done, pelvic ultrasound or MRI, and diagnostic laparoscopy if endometriosis is suspected.
5. Once an underlying cause is identified, direct therapy at that cause (e.g., surgical management such as laser ablation or electrofulguration of endometriosis); dysmenorrhea resulting from heavy menstrual bleeding improves once the bleeding itself is controlled.
6. For a patient with overlapping chronic pelvic pain and possible neuropathic pain features, consider adding a neuromodulator alongside ongoing gynecologic management — amitriptyline 10-25 mg PO at bedtime, or gabapentin starting at 100-300 mg PO at bedtime and titrated as tolerated.
7. Reserve surgical intervention (laparoscopic uterosacral ligament resection, presacral neurectomy, or hysterectomy with or without oophorectomy) for pain that persists despite adequate pharmacotherapy and, where relevant, conservative surgical management of an identified cause.

• Starting the NSAID only after pain is already severe, rather than scheduling it to begin at or just before the onset of symptoms or menses.
• Using PRN dosing instead of a regularly scheduled dose for the first 2-3 days of the cycle.
• Skipping the initial loading dose, which helps achieve faster symptom relief.
• Reaching for acetaminophen as a first-line agent — it is measurably less effective than an NSAID for dysmenorrhea.
• Assuming severe menstrual pain in a young patient is simply normal cramping and not offering treatment.
• Missing secondary dysmenorrhea in a patient over 30 with new-onset pain, or in any patient refractory to an adequate first-line trial.
• Ordering pelvic imaging routinely before a therapeutic trial when the history is a classic primary-dysmenorrhea pattern with a normal examination.
• Not asking whether the patient also wants contraception — a missed opportunity to select a combined hormonal contraceptive that treats both at once.
• Withholding hormonal contraception while investigations for suspected secondary dysmenorrhea are still pending, when it could be relieving symptoms in the meantime.

How to use this table: Doses are adult doses and require patient-specific confirmation. All NSAIDs listed are contraindicated in ASA hypersensitivity, active peptic ulcer disease or GI bleeding, significant renal impairment, and clotting disorders — confirm before selecting an agent. Select any drug name to open its complete Pharmasist Drug Database page.

NSAIDs — COX-2 inhibitor

An option for a patient at higher risk of GI adverse effects, or with NSAID/ASA hypersensitivity depending on the specific reaction type.

NSAIDs — propionic acid derivatives

NSAIDs — fenamates

NSAIDs — acetic acid derivatives

Simple analgesic (NSAID alternative)

Reserve for a patient with a genuine NSAID contraindication — measurably less effective than an NSAID for dysmenorrhea.

Combined hormonal contraceptives

Inhibit ovulation, limiting endometrial growth and menstrual prostaglandin production. An ideal first-line choice when the patient also wants contraception. Continuous or extended-cycle regimens decrease the frequency of periods and the prevalence of pain and are generally preferable to cyclic regimens; this also ameliorates dysmenorrhea due to endometriosis or adenomyosis.

Progestin-only options

Effective for dysmenorrhea whether the cause is primary or secondary (e.g., adenomyosis, endometriosis); can be started while investigations for secondary dysmenorrhea are still pending.

Natural health products

Evidence quality is generally low across this category as a whole; ginger has the most supportive data.

Adjuncts for refractory pain with chronic/neuropathic features

Consider alongside — not instead of — ongoing gynecologic management for a patient with poorly controlled dysmenorrhea and overlapping chronic pelvic pain.

Evidence note: Drug inventory, dosing, adverse effects, and comments reflect standard Canadian practice, cross-checked against the current SOGC guideline and current Cochrane evidence.^[1]