Why does perimenopause cause irregular periods?

During perimenopause, the ovaries may not release an egg in every cycle, and ovulation may happen at different points. Estrogen can rise and fall unevenly, while progesterone may be lower in cycles without ovulation. As a result, bleeding can come closer together or farther apart, last a different number of days, or vary from spotting to a heavier flow. A changing pattern alone cannot confirm the cause, because pregnancy, thyroid problems, medicines, fibroids, and other conditions can also affect bleeding.

Record the first day of bleeding, how long it lasts, whether the flow is light or heavy, and any pain or bleeding between periods. This record helps a clinician see the pattern. If pregnancy is possible, take a pregnancy test. Rest, drink fluids, and use period products that suit your flow; avoid taking hormonal or bleeding treatments without medical advice.

Arrange medical advice for a new or persistent change, bleeding after sex, bleeding between periods, or bleeding after menopause. Seek urgent care for very heavy bleeding with dizziness, faintness, shortness of breath, severe pain, or weakness. Prompt assessment is also sensible if bleeding is disrupting daily activities or you may be pregnant.

Could this pattern fit perimenopause, and what other causes should be checked? Do I need a pregnancy test, blood tests, or an examination? What amount or duration of bleeding should prompt urgent help?