Menstrual Cycle
Irregularity Checker
Up to 25% of women have irregular cycles. Common does not mean normal. This tool uses clinical definitions from ACOG and NICE to name your pattern, identify what might be causing it, and give you the exact language to use with your GP.
Irregular periods are common.
Common does not mean normal.
This tool maps your cycle pattern to clinical definitions — polymenorrhoea, oligomenorrhoea, menorrhagia — and tells you which conditions are worth investigating based on your specific symptoms.
It takes 2–3 minutes. Your result includes the clinical language to use with your GP.
Why irregular periods deserve investigation
Irregular menstrual cycles affect up to 14–25% of women of reproductive age, yet the majority are dismissed with "some women just have irregular cycles." There is a clinically important difference between a cycle that varies by 2–3 days and one that varies by 10–14 days, skips months, or produces soaking-level bleeding — and each pattern points to a different underlying cause.
ACOG and NICE define six clinically distinct patterns of irregularity: polymenorrhoea (cycles under 21 days), oligomenorrhoea (cycles over 35 days), amenorrhoea (absent periods), menorrhagia (heavy or prolonged bleeding), hypomenorrhoea (very light or short periods), and significant cycle variability (variation of more than 7 days between cycles). Each pattern has an associated set of conditions — including PCOS, thyroid dysfunction, endometriosis, adenomyosis, and premature ovarian insufficiency — that are largely treatable once identified.
The average woman waits 7–9 years for an endometriosis diagnosis. Knowing the clinical name for your pattern — and the tests your GP should be offering — is the first step to shortening that timeline.