Irregular periods: what counts as irregular, the causes, and when to act

What normal actually is

A normal adult cycle runs from 21 to 35 days, with bleeding for two to seven days. Some month-to-month variation is normal; variation of more than about seven to nine days between cycles is not.

In the first two years after periods start, and in the years approaching menopause, irregular cycles are expected and usually need no treatment.

Irregular means: cycles shorter than 21 or longer than 35 days, wide variation between cycles, bleeding between periods, or no periods for three months (amenorrhoea).

The causes

Hormonal: PCOS (the commonest), thyroid disease — both underactive and overactive — and high prolactin, which can also cause milky discharge from the breasts.

Weight and lifestyle: significant weight gain or loss, very low body weight, intense exercise, chronic stress, disturbed sleep and shift work. Undernutrition and eating disorders are important causes in young women.

Structural: fibroids, polyps, adenomyosis and endometriosis — more often causing heavy or painful periods than irregular ones. Also relevant in India: genital tuberculosis, which can reduce or stop periods and damage the tubes silently.

Other: pregnancy (always the first thing to exclude in a missed period), breastfeeding, recently stopping hormonal contraception, some medicines, uncontrolled diabetes, chronic illness, and the perimenopause.

Tests and treatment

The usual first set: a pregnancy test, thyroid function, prolactin, blood sugar, haemoglobin, and a pelvic ultrasound. Depending on the picture: hormone profile, AMH, and tests for PCOS or tuberculosis.

Treatment follows the cause: thyroid or prolactin correction, weight and activity change, treatment of anaemia, hormonal treatment to regulate cycles, and ovulation induction for women trying to conceive.

Heavy bleeding deserves its own attention: it is a leading cause of anaemia in Indian women, and it is treatable — with tranexamic acid, hormonal treatment, an intrauterine hormonal device, or surgery for fibroids and polyps. Soaking through pads hourly, passing large clots, or flooding at night is not something to endure quietly.

Cycles that are irregular for years, particularly with fewer than eight periods a year, need a plan even without fertility goals — for anaemia and for the uterine lining.

When to see a doctor

Same-day: heavy bleeding soaking a pad an hour or with dizziness and breathlessness; severe pelvic pain; a missed period with one-sided pain and bleeding (possible ectopic pregnancy); fever with pelvic pain; or bleeding after intercourse with pain.

Book an appointment for: no periods for three months; cycles under 21 or over 35 days; wide variation between cycles; bleeding between periods or after intercourse; periods so heavy or painful that they stop you working or studying; any bleeding after menopause; or milky nipple discharge when not breastfeeding.

This article is general information, not medical advice, and is no substitute for personal medical advice. For any decision about your or your child's health, please consult your doctor.

Frequently asked questions

Q: My periods stopped after I lost weight. Is that a problem? — Yes, and it needs assessment. Periods stopping with weight loss or intense exercise reflects the body shutting down reproduction, and prolonged absence affects bone density as well as fertility.

Q: Can stress alone stop periods? — Severe stress can delay or stop them, but it is a diagnosis reached after excluding pregnancy, thyroid disease, prolactin problems and PCOS — not a first assumption.

Q: Are period-delaying tablets safe for a wedding or a trip? — Prescribed short-term tablets to postpone a period are commonly used and generally safe for occasional use, but they should come from a doctor rather than a chemist, and not repeatedly.

Q: Do irregular periods mean I cannot conceive? — Not at all. Irregular ovulation makes timing harder and needs assessment, but ovulation induction and treatment of the underlying cause work well for most women.