What can cause irregular periods?

Irregular periods may be due to changing ovulation, hormonal conditions, medicines, stress, or life-stage changes. The timing, amount of bleeding, associated symptoms, and possibility of pregnancy help guide the next step. One irregular cycle cannot establish the cause.

With Anovulation, the ovary does not release an egg in a cycle, so bleeding may be late or absent. Polycystic Ovary Syndrome may combine irregular ovulation with acne or increased facial hair. Perimenopause can bring changing cycle length and flow, whereas Premature Ovarian Insufficiency may cause infrequent or absent periods earlier than expected. Stress, illness, major activity changes, and some medicines can temporarily affect hormone signals. A clinician may also consider thyroid or other hormone problems.

Write down bleeding dates, duration, flow, pain, spotting, medications, contraception, sleep, stress, and major weight or exercise changes. Check for pregnancy when relevant. Arrange a routine appointment when irregularity persists, returns repeatedly, or comes with acne, excess hair, hot flushes, nipple discharge, or pelvic pain. Treatment targets the reason: some people may be offered the Combined Pill for cycle management, while Metformin for PCOS is considered only when PCOS-related features fit.

Seek urgent care for severe pelvic pain, faintness, marked weakness, or heavy bleeding that is difficult to manage. Get prompt assessment for bleeding during possible pregnancy, bleeding after sex, or repeated bleeding between periods. The Irregular Periods page can help you organise the symptoms to mention.

Which causes fit my age, symptoms, and cycle history? Do I need a pregnancy test or hormone assessment? Could my medicines or contraception be contributing? What changes should I report quickly? If I want pregnancy, how might this affect ovulation planning?