Irregular Periods: 10 Common Causes and How They're Treated

Your cycle is a monthly report on your hormonal health. When it becomes irregular — cycles shorter than 21 days, longer than 35, or varying widely — something has shifted. Here are the ten causes we see most often in the clinic, and how each is addressed.

1. Polycystic ovary syndrome

The commonest cause in women under 40. Cycles stretch to 40, 60 or 90 days; acne, excess hair and weight gain often accompany it. Managed with lifestyle change, cycle regulation and, when conceiving, ovulation induction. See PCOS care.

2. Thyroid disorders

An underactive thyroid causes heavy, infrequent periods; an overactive one causes light, scanty periods. A TSH test and thyroid treatment usually restore cycles within months.

3. High prolactin

Raised prolactin — from stress, medications or a small pituitary adenoma — suppresses ovulation. Treated with medication after the cause is identified.

4. Stress, illness and travel

Any significant stress can delay ovulation for that cycle. Usually self-limiting.

5. Weight change and exercise

Rapid weight loss, low body fat or heavy training can stop periods altogether (hypothalamic amenorrhoea); weight gain worsens PCOS. Restoring a healthy weight is the treatment.

6. The years after the first period

Cycles are commonly irregular for one to two years after periods begin. Evaluation is needed only if they remain irregular beyond that, are very heavy, or very painful. See adolescent gynecology.

7. Perimenopause

From the early forties, cycles may shorten, then lengthen and skip, sometimes with heavier bleeding. Hormonal treatment can regulate bleeding and relieve symptoms. See menopause care.

8. Contraception

Hormonal methods change bleeding patterns — often lighter or absent periods on the pill, injection or hormonal IUD, and spotting in the first months. Usually harmless, but worth discussing if troublesome.

9. Fibroids, polyps and adenomyosis

These cause heavy, prolonged or irregular bleeding rather than missed periods. Diagnosed on ultrasound; treated medically or with hysteroscopic/laparoscopic surgery. See fibroid treatment.

10. Early pregnancy or its complications

A late period followed by irregular bleeding may be an early pregnancy, a miscarriage or, rarely, an ectopic pregnancy. A pregnancy test is always the first step.

When to see a doctor

Cycles consistently outside 21–35 days, no period for three months, bleeding between periods or after intercourse, or heavy bleeding with fatigue. Evaluation is simple — history, examination, a few blood tests and an ultrasound — and most causes are treatable. See irregular periods treatment in Indirapuram.

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