Why Are My Periods Suddenly So Heavy in My 40s?
Written with Autumn — The Change’s on-device AI perimenopause coach.
The short answer
Periods can become heavier or less predictable as menopause approaches. But a sudden or very heavy period isn’t something to automatically file under perimenopause. Bleeding that lasts more than 7 days, needs a pad or tampon change every 1 to 2 hours, passes larger clots, leaks through clothes or bedding, or is disrupting your life is worth discussing with a clinician.
What may be happening
Perimenopause can change the timing, duration and flow of periods. The NHS notes that periods can sometimes become heavy when you are approaching menopause. It is one possibility, not an answer on its own.
Heavy bleeding can also have other causes, including fibroids, endometriosis, adenomyosis, conditions that affect clotting, some medicines and other conditions affecting the womb or ovaries. Rarely, heavy periods can be a sign of womb cancer. This is not a reason to assume the worst; it is a reason not to assume the cause without an assessment.
What counts as heavy?
- Changing a pad or tampon every 1 to 2 hours, or emptying a menstrual cup more often than recommended.
- Needing to use two types of period product together.
- Bleeding for more than 7 days.
- Passing clots larger than about 2.5cm.
- Bleeding through clothes or bedding.
- Missing exercise, work or normal activities because of the bleeding.
- Feeling tired or short of breath often.
Why it can happen around perimenopause
Hormonal and cycle changes can make bleeding vary as menopause approaches. But bleeding is also affected by the lining of the womb, ovulation patterns, fibroids, adenomyosis, endometriosis, medicines and conditions that affect clotting. A period becoming heavier is information to bring to a clinician, not evidence that the change is harmless.
What may help
You don’t need a perfect log. When you speak with a clinician, it helps to describe when bleeding starts and stops, how often you change products, whether you pass clots, whether you bleed between periods or after sex, how much pain you have and how it affects daily life. You can use a voice note if that is easier than writing everything down. Bring a list of medicines and contraception as well.
A clinician may ask about the bleeding and related symptoms, examine you when appropriate, and arrange tests such as blood tests or scans depending on the pattern. Heavy bleeding can be associated with iron-deficiency anaemia, so ongoing tiredness or shortness of breath is important to mention.
When to talk to a clinician
Arrange an appointment if heavy bleeding is affecting your life, has continued for some time, comes with severe period pain, happens between periods or after sex, or occurs with pain when you pee, poo or have sex. Ask for advice rather than waiting for it to become “normal” just because you are in your 40s.
Seek urgent care when appropriate
If the bleeding is severe and you feel faint, very dizzy, short of breath or acutely unwell, seek urgent medical help. If you have recently missed a period and have unusual bleeding with abdominal or pelvic pain, seek urgent advice.
Questions women often ask
Can perimenopause cause heavy periods?
It can be part of the picture as periods change approaching menopause, but heavy bleeding has several possible causes. A change in flow deserves attention if it is persistent, disruptive or worrying.
Is a 7-day period automatically abnormal?
The NHS lists periods lasting more than 7 days as one sign that bleeding may be heavy. Your overall pattern and its effect on your life still matter, so discuss concerns rather than relying on one measure.
What should I notice before an appointment?
It helps to be able to describe dates, duration, product changes, clots, pain, bleeding between periods or after sex, tiredness, shortness of breath, medicines and how the bleeding affects your activities. A voice note can be easier than trying to remember everything in the appointment.
Related reading
Still trying to connect the dots?
If your bleeding is changing alongside sleep, temperature, mood or energy, Autumn can help you organise what you’re noticing and prepare a clear question for a healthcare professional. She is the private, on-device AI coach inside The Change—not a clinician.
Sources & evidence
- Heavy periods — NHS
- What are menopause and perimenopause? — NHS
- Understanding menopause — University College London Hospitals NHS Foundation Trust
- Vaginal bleeding between periods or after sex — NHS
Sources checked: 17 September 2026.