Managing Irregular Menstrual Cycles
Begin by ruling out pregnancy, sexually transmitted infections, medication interactions, and pathologic uterine conditions before initiating any treatment for irregular menses. 1
Define Your Patient's Irregularity
Irregular menstruation is defined as cycle length less than 21 days or greater than 35 days, with abnormal blood flow patterns. 2 It is abnormal for cycles to be absent for greater than 90 days (3 months), even in adolescents during early gynecologic years. 3
Initial Diagnostic Workup
Obtain these specific details:
- Bleeding pattern documentation: frequency, duration, amount of flow, and whether pain is present 1
- Pregnancy test: mandatory in all reproductive-age women with abnormal bleeding 1
- Timing-specific hormone testing (days 3-6 of cycle if possible): 1
- LH and FSH (LH/FSH ratio >2 suggests PCOS)
- Prolactin (>20 μg/L is abnormal)
- Mid-luteal progesterone (<6 nmol/L indicates anovulation)
- Testosterone (>2.5 nmol/L suggests PCOS)
- Glucose/insulin ratio (>4 suggests reduced insulin sensitivity)
- Physical examination: assess for hirsutism and acne indicating hyperandrogenism 1
Common pitfall: PCOS affects 4-6% of the general population but is often missed without proper hormone evaluation. 1
Treatment Algorithm Based on Bleeding Pattern
For Irregular Timing WITHOUT Heavy Bleeding
First-line treatment: NSAIDs for 5-7 days during bleeding episodes 1, 4
- Mefenamic acid 500 mg three times daily for 5 days, OR
- Celecoxib 200 mg daily for 5 days
For Heavy or Prolonged Irregular Bleeding
First-line treatment: Low-dose combined oral contraceptives (30-35 μg ethinyl estradiol) for 10-20 days 1, 4
Important caveat: Combined hormonal contraceptives increase venous thromboembolism risk three to fourfold. 1
Alternative for estrogen-contraindicated patients: Levonorgestrel 20 μg/day intrauterine device reduces menstrual blood loss by 71-95%. 1
For Secondary Amenorrhea (Absent Periods in Previously Menstruating Women)
When progesterone deficiency is confirmed: Progesterone capsules 400 mg orally at bedtime for 10 days 5
Critical warning: Progesterone capsules contain peanut oil and are contraindicated in peanut allergy. 5 Some women experience drowsiness, dizziness, blurred vision, difficulty speaking, or difficulty walking after taking progesterone—take at bedtime in standing position with water. 5
Enhanced Counseling Reduces Discontinuation
Provide specific expectations about bleeding patterns when initiating hormonal treatments, as this significantly reduces method discontinuation. 1, 4 Explain that irregular spotting is common during the first 3-6 months of continuous hormonal contraceptives and generally decreases with continued use. 4
When to Refer or Escalate
Refer to specialist if: 1
- Irregular bleeding persists despite first-line treatment and is unacceptable to the patient
- Suspected PCOS requires specialized management (particularly in women with epilepsy, who have 10-25% PCOS prevalence versus 4-6% general population)
- Amenorrhea persists beyond 3 months despite treatment
Follow-Up Protocol
Schedule follow-up within 2-3 months to monitor treatment response. 1 Reassess bleeding patterns, medication adherence, and side effects. Discuss whether continued treatment remains necessary. 5
Long-term health implications: Irregular menstruation associates with increased risk of metabolic syndrome, coronary heart disease, type 2 diabetes, osteoporosis, and pregnancy-related hypertensive disorders. 2 Estrogen deficiency from prolonged amenorrhea increases osteoporosis and hip fracture risk. 3 View the ovary as an important endocrine organ requiring protection, especially for bone health. 3