Irregular periods

A regular cycle runs roughly every 24–38 days. Irregular periods means the interval varies markedly, becomes long (oligomenorrhoea) or absent (amenorrhoea), or bleeding is unpredictable. Irregularity is normal in the first couple of years after periods begin and during the perimenopausal transition. In between, the common drivers cluster into: hormonal axis problems — PCOS (by far the most common), thyroid disease (both over- and under-active), high prolactin, and hypothalamic causes (low body weight, over-exercise, stress); structural causes — fibroids, polyps; and pregnancy, which must always be excluded first. The pattern of irregularity plus accompanying features (weight change, acne and hair growth, galactorrhoea, hot flushes) points to the cause.

• PCOS — the commonest cause of chronic irregular/infrequent periods; often with acne, excess hair, weight gain.
• Thyroid disease — both hypo- and hyperthyroidism disrupt cycles.
• High prolactin — from a pituitary adenoma or medication; may come with milk-like nipple discharge.
• Perimenopause — irregular cycles in the 40s–early 50s.
• Hypothalamic — low body weight, intensive exercise, stress, eating disorders.
• Pregnancy — always excluded first in a missed period.
• Structural — fibroids, endometrial polyps (usually heavy/unpredictable bleeding).
• Contraception — hormonal methods change or stop bleeding (expected).

First step is always a pregnancy test. Then a targeted panel: TSH (thyroid), prolactin (pituitary), and — if PCOS is suspected from acne/hair/weight — total testosterone, SHBG and free-androgen estimate. FSH, LH and estradiol help locate the problem (high FSH suggests ovarian/menopausal; low FSH/LH suggests hypothalamic). Timing hormone draws to the cycle helps when cycles are trackable. Pelvic ultrasound assesses ovaries (polycystic morphology) and the uterus (fibroids, polyps, lining thickness). Mediora.AI surfaces the thyroid, prolactin and androgen pattern from your results; the gynaecological diagnosis and any imaging belong with your GP or gynaecologist.