Quick Answer: Irregular periods (cycles shorter than 21 or longer than 35 days, varying 7+ days, or missing periods) affect 14-25% of women. Common causes: PCOS (most common), stress, weight changes, thyroid issues, perimenopause. See doctor if: missed 3+ periods, trying to conceive, severe pain, bleeding between periods. Treatment depends on cause: hormonal birth control, lifestyle changes, treating underlying conditions. Most irregular periods have treatable causes - don't accept them as normal.
If your periods arrive like unexpected guests - sometimes on time, sometimes weeks late, sometimes not at all - you're dealing with irregular cycles. While occasional irregularity can be normal, consistent unpredictability often signals an underlying issue that deserves attention. Let me help you understand what's happening and what to do about it.
What's Normal vs. Irregular?
Normal Menstrual Cycle:
- Length: 21-35 days (counted from first day of one period to first day of next)
- Consistency: Varies by less than 7 days cycle to cycle
- Duration: 3-7 days of bleeding
- Average: 28 days (but 21-35 all normal)
Irregular Periods Defined As:
- Too short: Cycles less than 21 days
- Too long: Cycles longer than 35 days
- Inconsistent: Varying by more than 7-9 days
- Missed periods: Amenorrhea (absent periods)
- Unpredictable: Can't anticipate when period will arrive
When Irregularity Is Normal:
- First 2 years after menarche: Cycles establishing
- Perimenopause: Hormones fluctuating (40s-early 50s)
- Postpartum: Especially if breastfeeding
- After stopping birth control: May take 3-6 months to regulate
- Occasional variation: 1-2 irregular cycles per year from stress/illness
What Causes Irregular Periods?
1. PCOS (Polycystic Ovary Syndrome)
- Frequency: Most common cause (affects 10% of women)
- Signs: Irregular periods, excess hair, acne, weight gain
- Diagnosis: Blood tests, ultrasound
- Treatment: Birth control, metformin, lifestyle changes
2. Stress
- How: Cortisol disrupts reproductive hormones
- Can cause: Delayed ovulation, missed periods
- Fix: Stress management, adequate sleep, relaxation techniques
3. Weight Changes
- Too low: BMI under 18.5 can stop periods
- Too high: Excess fat produces estrogen, disrupting balance
- Rapid changes: Quick weight loss/gain affects hormones
4. Excessive Exercise
- Athletic amenorrhea: Common in endurance athletes
- Cause: Low body fat + high energy expenditure
- Fix: Reduce training volume, increase calories
5. Thyroid Disorders
- Hypothyroidism: Heavy, irregular periods
- Hyperthyroidism: Light, infrequent periods
- Easy to test: TSH blood test
- Treatment: Thyroid medication normalizes cycles
6. Other Causes:
- Perimenopause (40s-50s)
- Medications (antidepressants, blood thinners)
- Chronic illness
- Eating disorders
- Pituitary disorders
- Premature ovarian insufficiency
How to Regulate Irregular Periods
Medical Treatments:
- Birth control pills: Regulate cycles, most common treatment
- Hormonal IUD: Regulates bleeding
- Metformin: For PCOS-related irregularity
- Thyroid medication: If thyroid disorder
- Progestin therapy: Regulates hormones
Lifestyle Approaches:
- Achieve healthy weight (BMI 18.5-25)
- Manage stress consistently
- Moderate exercise (avoid overtraining)
- Adequate sleep (7-9 hours)
- Balanced nutrition (avoid extreme restriction)
- Inositol supplements if PCOS
The Bottom Line on Irregular Periods
Key Takeaways:
- Normal cycles are 21-35 days, varying less than 7 days
- Irregular periods affect 14-25% of women
- Most common cause: PCOS (easily diagnosed and treatable)
- Other causes: stress, weight changes, thyroid, excessive exercise
- See doctor if: missed 3+ periods, trying to conceive, severe symptoms
- Most irregular periods have treatable underlying causes
- Birth control pills most effective regulation method
- Lifestyle changes help stress/weight-related irregularity
Irregular periods are frustrating and often indicate an underlying condition that deserves medical attention. Don't accept them as "just how your body is" - most causes are treatable. Track your cycles, identify patterns, and work with a healthcare provider to find the right solution for you.
Medical Disclaimer: This article is informational, not medical advice. Always consult healthcare providers for menstrual irregularities, especially if trying to conceive or experiencing severe symptoms.