What causes heavy menstrual cycles and how are they treated?

Heavy Menstrual Bleeding: Causes and Treatment

Causes of Heavy Menstrual Bleeding

Heavy menstrual bleeding stems from two main categories: structural abnormalities and non-structural causes, systematically classified by the PALM-COEIN system. 1

Structural Causes (PALM)

• Polyps: Endometrial polyps, particularly common in women over 40 years of age 2
• Adenomyosis: Endometrial tissue growing into the uterine muscle wall 1
• Leiomyoma (fibroids): Most common structural cause in women under 40 years, including submucosal and other myomas 1, 2
• Malignancy and hyperplasia: Endometrial cancer or precancerous changes requiring immediate evaluation 1

Non-Structural Causes (COEIN)

• Coagulopathy: Up to 20% of women with heavy menstrual bleeding have an underlying inherited bleeding disorder, most commonly von Willebrand disease 3, 4, 5
• Ovulatory dysfunction: Anovulation or oligo-ovulation causing irregular, heavy bleeding due to unopposed estrogen stimulation 1
• Endometrial: Primary endometrial disorders affecting hemostasis 1
• Iatrogenic: Medication-induced bleeding, including anticoagulants and certain contraceptives 1
• Not yet classified: Other causes not fitting above categories 1

Specific Conditions Causing Anovulation

• Adolescence and perimenopause (physiologic) 1
• Polycystic ovary syndrome and other hyperandrogenic conditions 1, 4
• Thyroid disease and hyperprolactinemia 1, 4
• Hypothalamic dysfunction and primary pituitary disease 1
• Premature ovarian failure 1
• Medications (antipsychotics, antiepileptics) 4

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Essential Initial Assessment

Before initiating treatment, rule out pregnancy in all reproductive-age women, assess for structural pathology, and screen for coagulopathies. 3

Required Evaluation Steps

• Pregnancy test (beta-hCG) in all reproductive-age women 1, 3
• Thyroid-stimulating hormone and prolactin levels 1
• Transvaginal ultrasonography to identify fibroids, polyps, or adenomyosis 1, 4
• Saline infusion sonohysterography or hysteroscopy for better visualization of intracavitary lesions 1, 2
• Endometrial biopsy for women ≥35 years with recurrent anovulation, women <35 years with endometrial cancer risk factors, or those with bleeding unresponsive to medical therapy 1, 4
• Bleeding score assessment to identify women requiring hematologic investigation for inherited bleeding disorders 5

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First-Line Medical Treatment

NSAIDs are the recommended first-line pharmacologic treatment, prescribed for 5-7 days during menstruation only. 3

NSAID Therapy Details

• Effective agents: Mefenamic acid, naproxen, indomethacin, flufenamic acid, and diclofenac sodium reduce menstrual blood loss by 20-60% 3, 2
• Duration: Limit to 5-7 days during active bleeding only 3
• Critical contraindication: Avoid NSAIDs entirely in women with cardiovascular disease due to increased risk of myocardial infarction and thrombosis 3
• Important caveat: Never use aspirin—it does not reduce bleeding and may paradoxically increase blood loss in women with lower baseline menstrual blood loss 3, 6

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Second-Line Medical Treatment

The levonorgestrel-releasing intrauterine device (LNG-IUD) is the most effective medical treatment for heavy menstrual bleeding, reducing blood loss by 71-95%. 3, 6, 5

LNG-IUD Advantages

• Effectiveness comparable to endometrial ablation or hysterectomy 2, 7
• Over time, many women experience only light menstrual bleeding or amenorrhea 3
• Can be used through menopause in perimenopausal women 3
• Particularly beneficial for women on antiplatelet therapy 6

Alternative Second-Line Options

Tranexamic acid (non-hormonal):

• Reduces menstrual blood loss by approximately 80 mL per cycle (40-60% reduction) 3, 6, 2
• Absolute contraindications: Active thromboembolic disease, history of thrombosis, or cardiovascular disease 3, 6, 5
• More expensive than other options 6, 2

Combined hormonal contraceptives:

• Effective for ovulatory dysfunction-related bleeding 1
• Requires careful cardiovascular and thrombotic risk assessment in perimenopausal women 6

Progestin-only contraception:

• Appropriate for anovulatory bleeding 1
• Cyclic progestogens do NOT significantly reduce bleeding in women who ovulate 2

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Treatment Algorithm Based on Bleeding Pattern

For Anovulatory Bleeding

• Start NSAIDs for 5-7 days during bleeding 3, 6
• Add combined oral contraceptives or progestin therapy if bleeding persists 1, 6
• Consider LNG-IUD for long-term management 3

For Ovulatory Bleeding (Menorrhagia)

• Start NSAIDs for 5-7 days during menstruation 3
• If inadequate response, advance to LNG-IUD (most effective) 3, 4
• Alternative: Tranexamic acid if no thrombotic contraindications 3, 5

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Surgical Options When Medical Treatment Fails

If medical treatment fails, is contraindicated, or not tolerated, or if significant intracavitary lesions are present, surgical intervention may be necessary. 1

Surgical Approaches

• Polypectomy or fibroidectomy for identified structural lesions 4
• Endometrial ablation (low operative morbidity, outpatient procedure) 4, 5, 7
• Uterine artery embolization for fibroids 4, 7
• Hysterectomy as definitive treatment when other options fail 1, 4, 5

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Critical Counseling Points

Enhanced counseling about expected bleeding patterns and reassurance that bleeding irregularities with certain treatments are normal can significantly improve treatment adherence. 3

Key Messages for Patients

• Unscheduled spotting or light bleeding is expected during the first 3-6 months of LNG-IUD use and generally decreases with continued use 1, 6
• Amenorrhea with LNG-IUD is not harmful and does not require treatment 1
• NSAID therapy should be taken during bleeding days only, not continuously 3
• Women taking progesterone capsules may experience drowsiness, dizziness, or blurred vision and should take medication at bedtime while standing 8

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Common Pitfalls to Avoid

• Do not use aspirin for heavy menstrual bleeding—it may worsen bleeding 3, 6
• Do not prescribe NSAIDs without screening for cardiovascular disease 3
• Do not use tranexamic acid in women with any history of thrombosis 3, 6
• Do not assume cyclic progestogens work for ovulatory bleeding—they are ineffective 2
• Do not dismiss bleeding in first 3-6 months of IUD use as abnormal—it is expected and generally resolves 1, 6
• Do not forget to rule out pregnancy before initiating any treatment 3
• Do not overlook coagulopathy screening in women with heavy bleeding since adolescence 3, 5