Heavy Menstrual Bleeding

Heavy menstrual bleeding (HMB) — the term that has replaced "menorrhagia" — is abnormal uterine bleeding (AUB) with excessive menstrual blood flow that interferes with a patient's quality of life, and it commonly causes or coexists with iron-deficiency anemia.^[1] It can occur with an otherwise regular, predictable cycle or alongside irregular, unpredictable bleeding — the pattern itself is a clue to the underlying cause, since regular-cycle HMB more often reflects a structural or local endometrial cause while irregular bleeding more often reflects ovulatory dysfunction. The FIGO PALM-COEIN system is the standard framework for classifying the underlying cause into structural (Polyp, Adenomyosis, Leiomyoma, Malignancy/hyperplasia) versus non-structural (Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not-otherwise-classified) categories, and this classification directly determines the workup and treatment pathway.^[2] Pharmacologic therapy — non-hormonal (tranexamic acid, NSAIDs) or hormonal (most effectively the levonorgestrel-releasing intrauterine system) — is first-line for most patients; surgical options are reserved for patients who do not desire future fertility, decline medical therapy, or fail it.

HMB is a clinical diagnosis built on history rather than a specific physical sign. Patients describe one or more of: prolonged menses (bleeding lasting longer than 7 days), soaking through a pad or tampon in less than 1-2 hours on the heaviest days, needing to use double protection (pad plus tampon) to control flow, passing clots larger than about 2.5 cm (roughly the size of a quarter), needing to change protection overnight, or restricting work, school, exercise, or social activities because of bleeding volume or the fear of an accident. Ask directly about the impact on daily activities and quality of life — this is now the clinically preferred way to gauge severity, rather than trying to estimate a precise blood-loss volume, since patient-perceived impact and measured blood loss do not always track together.

Symptoms of the resulting iron-deficiency anemia — fatigue, exertional dyspnea, palpitations, lightheadedness, pallor, pica, or restless legs — are common presenting complaints in their own right and should prompt the same HMB workup even when the patient has not framed their visit as being about their periods.

Distinguish the bleeding pattern: regular, cyclic HMB (predictable timing, just heavier or longer than usual) points toward a structural or local endometrial cause and is generally ovulatory; irregular, unpredictable HMB (variable timing and/or volume) points toward ovulatory dysfunction (adolescence, perimenopause, PCOS, thyroid disease, hyperprolactinemia, eating disorder) or an iatrogenic cause. This distinction guides both the initial workup and the choice of first-line hormonal therapy if one is used.

• Adolescence — an immature hypothalamic-pituitary-ovarian axis produces anovulatory cycles, particularly in the first year after menarche.
• Perimenopause — anovulatory cycles become common again as ovarian function declines.
• Polycystic ovary syndrome and other causes of chronic anovulation.
• Hypothyroidism or hyperthyroidism.
• Hyperprolactinemia.
• Obesity — associated with both anovulation and unopposed estrogen exposure.
• Uterine fibroids (leiomyomas), endometrial or endocervical polyps, and adenomyosis.
• A bleeding disorder (most importantly von Willebrand disease) — especially relevant in adolescents with HMB since menarche, or anyone with a personal or family history of easy bruising, epistaxis, or heavy bleeding after dental extraction or childbirth.
• Anticoagulant therapy.
• An intrauterine device (copper IUDs increase menstrual blood loss; hormonal iatrogenic causes can also produce unscheduled bleeding).
• Risk factors for endometrial hyperplasia or malignancy: age over 40, BMI 35 or higher, diabetes, hypertension, unopposed estrogen exposure, nulliparity, PCOS, and a family history of endometrial cancer.
• Liver or renal disease affecting hormone metabolism or clotting factor synthesis/clearance.

History

Characterize the bleeding pattern (regular/cyclic versus irregular/unpredictable), duration, and impact on quality of life; ask specifically about flooding, clot size, pad/tampon changes, and overnight protection. Take a personal and family bleeding-disorder history, current medications (anticoagulants, hormonal therapy, an IUD), and screen for symptoms of thyroid disease, hyperprolactinemia, and PCOS.

Examination

Visual inspection of the vulva, vagina, and cervix; speculum and bimanual examination to assess for a visible lesion, cervical friability, uterine size/contour, and adnexal masses; general examination for pallor, thyromegaly, hirsutism/acne (PCOS), or bruising/petechiae suggesting a bleeding disorder.

Initial investigations

• Pregnancy test in anyone of reproductive potential.
• CBC to assess for anemia.
• Serum ferritin when anemia is confirmed, or when iron-deficiency symptoms are present even without frank anemia — iron-deficiency anemia is a near-universal comorbidity of HMB and needs its own directed treatment (see Treatment Targets and Special Populations).
• Thyroid function testing if the history or examination suggests thyroid disease — not a routine test in every HMB workup.
• Coagulation screening (including von Willebrand studies) for adolescents with HMB since menarche, or anyone with a personal/family bleeding-disorder history — this population has a meaningfully higher rate of an underlying bleeding disorder than adult HMB overall.
• Pelvic ultrasound (transvaginal preferred where feasible) as the first-line imaging test for structural causes.
• Endometrial biopsy in patients over 40 years of age, and in younger patients with risk factors for endometrial carcinoma (BMI 35 or higher, diabetes, hypertension, exposure to unopposed estrogen, nulliparity, PCOS, or a family history of endometrial cancer).
• MRI and/or hysteroscopy as second-line imaging when ultrasound is inconclusive or a structural lesion needs further characterization before treatment planning (e.g., fibroid mapping before myomectomy).

Laboratory testing for female sex hormones (FSH, LH, estradiol) is not routinely indicated in the initial workup of HMB with otherwise-regular ovulatory cycles.^[1]

Any treatment approach requires this search for uterine structural abnormalities alongside hormonal and hematologic causes; when a specific underlying cause is identified, directed therapy toward that cause should be added to symptomatic HMB treatment.^[1]

• Reduce menstrual blood loss to a volume that no longer interferes with the patient's physical, emotional, social, or material quality of life.
• Identify and correct iron-deficiency anemia — treat this directly with iron repletion, not merely by reducing bleeding volume and waiting for it to resolve on its own.
• Identify any specific underlying structural or functional cause (PALM-COEIN) and add directed therapy toward that cause when one is found.
• Provide effective contraception concurrently when the patient desires it, since several of the most effective HMB therapies are also highly effective contraceptives.
• Preserve fertility for patients who desire future pregnancy when choosing among otherwise-comparable options.
• Avoid unnecessary surgery when medical therapy can achieve adequate control and the patient prefers a uterine-preserving option.

• Have the patient track bleeding using a simple pad/tampon diary (product type, number used, degree of soaking, clot size, and days of flow) — this both quantifies severity at baseline and gives an objective way to judge whether treatment is working.
• Counsel on the correct timing of on-demand therapy: tranexamic acid and NSAIDs are taken only during the days of heavy flow (starting the day before or the first day of bleeding and continuing for 3-5 days or until flow subsides), not continuously through the cycle.
• Before LNG-IUS insertion, counsel explicitly that irregular spotting is expected for the first 3 to 6 months and does not mean the device has failed — advise waiting at least 6 cycles before judging the treatment's effect on bleeding volume.
• Iron-rich dietary counselling for patients with or at risk of iron-deficiency anemia, alongside — not instead of — oral iron supplementation when indicated.
• Encourage activity modification and realistic planning (e.g., having supplies on hand, layered clothing) on anticipated heavy-flow days while definitive treatment takes effect.
• Advise when to seek urgent care (see Red Flags & Refer) rather than waiting for a scheduled follow-up.

Surgical and procedural options are the non-pharmacologic endpoint for patients who have completed childbearing, decline medical therapy, or fail it. Endometrial ablation is a minimally invasive, uterine-preserving procedure (laser, electrocautery, resection, or heat-based) that destroys the endometrial lining and is highly effective at reducing bleeding, though a meaningful proportion of patients eventually need further intervention.^[1] Hysterectomy is the definitive treatment, with the highest rate of patient satisfaction of any option, and is increasingly performed through minimally invasive (vaginal, laparoscopic, or robotic) approaches. For patients who wish to preserve fertility with a structural fibroid-related cause, uterine artery embolization or myomectomy are alternatives to hysterectomy, and hysteroscopic resection is definitive treatment for small submucosal fibroids and endometrial polyps. Because this chapter is pharmacotherapy-focused, procedure selection, technique, and perioperative management are gynecologic surgical decisions outside its scope — the role of the pharmacist is to recognize when medical therapy has been adequately trialled and a surgical referral is the appropriate next step (see Treatment Failure & Next Step).

Pregnancy

Bleeding in pregnancy is, by definition, not heavy menstrual bleeding — pregnancy must always be excluded first, and pregnancy-related bleeding (threatened/incomplete miscarriage, ectopic pregnancy) is managed through the appropriate obstetric pathway, not this chapter's therapies. NSAIDs, GnRH agonists, danazol, elagolix, and combined hormonal contraceptives are not used in pregnancy. Tranexamic acid crosses the placenta; a risk-benefit discussion is required if genuinely needed for a separate indication during pregnancy, since available data have not clearly established or excluded a fetal risk with early-pregnancy exposure.^[4]

Breastfeeding

NSAIDs (standard doses) and progestin-only methods (LNG-IUS, oral progestins, DMPA) are compatible with breastfeeding; combined hormonal contraceptives are generally deferred until breastfeeding is well established given a theoretical effect on milk supply. Tranexamic acid passes into breast milk at only a small fraction of the maternal serum concentration, and current lactation-safety data do not show adverse effects on the breastfed infant — it is generally considered compatible with breastfeeding when clinically needed.

Adolescents

Screen for a bleeding disorder (especially von Willebrand disease) in any adolescent with HMB since menarche — this population has a meaningfully higher rate of an underlying coagulopathy than the general HMB population. Anovulatory cycles related to an immature hypothalamic-pituitary-ovarian axis are common and often normalize over the first year or two after menarche. The LNG-IUS and combined hormonal contraceptives remain first-line options in adolescents, sexually active or not, with individualized counselling on insertion/use. Tranexamic acid for the menorrhagia indication specifically is not authorized by Health Canada for patients under 18 years of age — clinical experience in this population was not available at the time of licensing — so weigh this against alternatives (NSAID, hormonal therapy) with an established evidence base in adolescents, and treat any such use as an individualized, specialist-informed decision rather than routine practice.^[4]

Perimenopausal and older reproductive-age patients

Endometrial pathology risk rises with age — apply a lower threshold for endometrial biopsy (age over 40, per Assessment & Diagnosis) and reassess the diagnosis rather than reflexively escalating the same HMB therapy if the bleeding pattern changes.

Renal impairment

Tranexamic acid requires dose reduction in renal insufficiency because blood levels rise with reduced clearance — see Drug Tables for the specific serum-creatinine-based adjustment. NSAIDs should generally be avoided in significant renal impairment.

Bleeding disorders / anticoagulant therapy

NSAIDs are contraindicated in patients with a known bleeding disorder. Tranexamic acid can be particularly useful in this population given its antifibrinolytic mechanism, but coordinate with hematology, since patients with a history or risk of thrombosis are themselves a contraindication to tranexamic acid — these are two different bleeding-related populations that need individualized, not interchangeable, reasoning.

Additional caution before starting tranexamic acid

Patients who are obese and diabetic, have PCOS or a first-degree relative with endometrial cancer, or are on unopposed estrogen or tamoxifen should discuss initiation with their prescriber first, given these patients' independently elevated endometrial-pathology risk profile.^[4]

Reassess bleeding severity and quality-of-life impact at each visit using the same pad/tampon-diary approach established at baseline, and recheck CBC (and ferritin if it was low) to confirm anemia is resolving on the chosen regimen plus iron repletion. For the LNG-IUS specifically, expect and counsel through irregular spotting during the first 3-6 months, and do not judge treatment effect before at least 6 cycles have passed. For tranexamic acid, the Canadian product monograph directs patients to consult their prescriber if bleeding is not reduced after 3 menstrual cycles of correctly-used therapy, and to switch to an alternative treatment if it remains inadequately controlled.^[4] Reassess ongoing need for and contraindications to hormonal therapy at least annually. Any new red-flag symptom — intermenstrual/postcoital bleeding, postmenopausal bleeding, or a new pelvic mass — should prompt re-investigation rather than simply adjusting the current HMB regimen. Patients on a GnRH agonist beyond 6 months need bone density monitoring; patients on danazol need periodic lipid and liver function monitoring given its adverse-effect profile; patients on tranexamic acid for several weeks or longer should have their vision monitored (sharpness, colour vision) given rare reports of visual disturbance, and the drug should be stopped if this occurs.^[4]

1. Confirm correct use: NSAID/tranexamic acid started at the right time (day before or day 1 of heavy flow) and continued long enough; LNG-IUS or CHC actually in place/being taken as directed.
2. Confirm structural workup has actually been done — pelvic ultrasound, and endometrial biopsy if age over 40 or risk factors are present — if therapy was started empirically before imaging.
3. If non-hormonal monotherapy (tranexamic acid or an NSAID alone) is inadequate, combine the two, or move to a hormonal option.
4. If a first-line hormonal option (LNG-IUS or CHC) is inadequate after an adequate trial (generally 3-6 months, allowing for the LNG-IUS's expected early irregular-bleeding phase), consider switching hormonal method, adding a cyclic/extended progestin, or a short-term trial of a GnRH agonist.
5. Reconsider or repeat imaging/biopsy if the bleeding pattern has changed since the last workup, rather than assuming the same diagnosis and simply intensifying the same treatment.
6. Refer for surgical evaluation (endometrial ablation, myomectomy/uterine artery embolization if fertility is desired, or hysterectomy if not) when medical therapy has genuinely failed, is contraindicated, or is declined by an informed patient.

• Treating postmenopausal bleeding empirically as HMB without investigation — it is endometrial cancer until proven otherwise.
• Missing coagulation screening in an adolescent with HMB since menarche.
• Prescribing an NSAID to a patient with a known bleeding disorder, active pelvic inflammatory disease, or significant renal impairment.
• Under-recognizing iron-deficiency anemia as "just heavy periods" — check CBC/ferritin and start iron repletion directly rather than assuming it will resolve once bleeding is controlled.
• Judging the LNG-IUS a failure before 3-6 cycles, when irregular spotting is the expected early pattern.
• Combining tranexamic acid with a combined hormonal contraceptive without weighing additional VTE risk factors (obesity, smoking, immobility).^[4]
• Continuing GnRH agonist monotherapy beyond 6 months without adding estrogen-progestogen add-back therapy for bone protection.
• Recommending or continuing ulipristal acetate (Fibristal) for fibroid-related HMB — it was voluntarily withdrawn from the Canadian market in 2020 for serious liver injury risk and remains unavailable; do not confuse it with the differently-dosed, differently-indicated single-dose emergency contraceptive product that shares the same molecule.^[5]
• Skipping endometrial biopsy in a patient under 40 who otherwise has clear risk factors for endometrial pathology.
• Starting a patient with irregular menstrual bleeding on tranexamic acid before the cause of the irregularity has been established, per Health Canada's own product-labelling caution.^[4]

How to use this table: Doses are adult doses and require patient-specific confirmation (renal/hepatic function, weight, allergy history). Pediatric dosing is weight-based per the current product monograph unless stated. Drug pricing is intentionally omitted. Select any drug name to open its complete Pharmasist Drug Database page.

Antifibrinolytics

NSAIDs

Start the day before or on the first day of heavy flow and continue 3-5 days or until bleeding subsides. Contraindications common to this class: hypersensitivity to ASA/NSAIDs, active pelvic inflammatory disease, significant renal impairment, or a bleeding disorder.

Oral and injectable progestins

Normalize the endometrial response to estrogen and reduce breakthrough bleeding; continuous use prevents menstrual flow entirely. Generally less effective than the LNG-IUS or a combined hormonal contraceptive for cycle control.

Levonorgestrel-releasing intrauterine system

The most effective medical treatment for HMB, and simultaneously highly effective long-acting reversible contraception.

Combined hormonal contraceptives

A monophasic product is used as a representative example -- any monophasic combined hormonal method (pill, patch, or ring) is a reasonable choice; confirm the full contraindication profile (VTE history, migraine with aura, uncontrolled hypertension, smoking over age 35, etc.) before initiating any combined hormonal method.

Gonadotropin-releasing hormone (GnRH) agonists

Usually given for 6 months or less, since long-term use causes a significant, only partly reversible decrease in bone mineral density. If continued beyond 6 months, add estrogen-progestogen add-back therapy to preserve bone health.

Gonadotropin-releasing hormone (GnRH) antagonist

Elagolix is approved by Health Canada only for moderate-to-severe endometriosis-associated pain -- using it specifically for fibroid-related HMB is off-label in Canada and should be reserved for specialist-directed use, with estrogen-progestogen add-back therapy to reduce hypoestrogenic effects.

Gonadotropin inhibitor (pituitary)

Poor tolerability from androgenic effects limits routine use to patients who have failed or cannot use other options.

Acute severe bleeding -- additional hospital-based option

Intravenous conjugated estrogen was historically used to promote rapid endometrial proliferation over exposed spiral arteries in acute severe HMB, always followed by a progestogen or combined hormonal contraceptive to stabilize the endometrium once bleeding is controlled. It is not consistently stocked in Canadian hospital pharmacies today, so tranexamic acid and high-dose oral hormonal tapers (see above) are the more practical first choices in most Canadian settings.