Understanding What Causes Heavy Periods
Heavy periods can be caused by many different things, including hormonal changes, fibroids, adenomyosis, endometriosis, polyps, thyroid problems, bleeding disorders, some medications, contraception changes, pregnancy-related issues, and changes around perimenopause.
You should see a GP if your periods are affecting your daily life, you are soaking through pads or tampons quickly, passing large clots, bleeding for more than 7 days, feeling tired or dizzy, bleeding between periods, bleeding after sex, or your periods have suddenly become much heavier than usual.
Key takeaways
Heavy periods are also called heavy menstrual bleeding or menorrhagia.
A period may be considered heavy if it interferes with your normal activities, requires very frequent pad or tampon changes, causes flooding or large clots, or leads to iron deficiency or anaemia.
Common causes include hormonal changes, fibroids, adenomyosis, endometriosis, polyps, thyroid disease, medications, contraception, bleeding disorders and perimenopause.
A GP can help identify the likely cause, check for iron deficiency, arrange tests if needed, and discuss treatment options.
If you live in Sydney’s eastern suburbs, Dr Amanda Henderson can help assess heavy periods and guide next steps.
Who this article is for
This article is for people who have noticed heavier periods and want to understand what might be causing them.
It may be especially relevant if you:
need to change pads or tampons more often than usual
bleed through clothing or bedding
need to use double protection
pass large blood clots
bleed for more than 7 days
feel exhausted, dizzy, short of breath, or low in energy
have pelvic pain as well as heavy bleeding
have bleeding between periods
have bleeding after sex
have recently started or changed contraception
are in your late 30s, 40s, or approaching menopause
are trying to work out whether your bleeding is “normal” or worth checking
What are heavy periods?
Heavy periods are periods where the amount or pattern of bleeding is more than expected and starts to affect your health, comfort, or daily life.
Heavy bleeding may look like:
needing to change a pad, tampon, menstrual cup, or period underwear very frequently
bleeding through clothes or bedding
needing to wake overnight to change sanitary protection
passing clots
needing to avoid exercise, work, social events, travel, or normal activities because of bleeding
feeling tired, weak, dizzy, or breathless around your period
being told you have low iron or anaemia
Some people have always had heavy periods. Others notice a change over time. Either pattern is worth discussing with a GP if it is affecting your life.
What causes heavy periods?
Heavy periods can have several possible causes. Sometimes there is one clear reason. Sometimes there are several contributing factors. In some cases, no serious cause is found, but treatment can still help.
Common causes of heavy periods
1. Hormonal changes
Hormonal changes are a common reason for heavy or irregular bleeding.
This can happen during:
the teenage years after periods first start
times of stress, weight change, or illness
polycystic ovarian syndrome
thyroid problems
perimenopause, which is the transition leading up to menopause
When ovulation is irregular, the lining of the uterus may build up differently and then shed in a heavier or less predictable way.
2. Fibroids
Fibroids are non-cancerous growths of the muscle of the uterus. They are common and can vary in size and position.
Fibroids can cause:
heavy periods
prolonged bleeding
pelvic pressure
bloating
frequent urination
fertility or pregnancy concerns in some cases
Not all fibroids cause symptoms. Whether they matter depends on their size, location, and the symptoms they cause.
3. Adenomyosis
Adenomyosis occurs when tissue similar to the lining of the uterus grows into the muscle wall of the uterus.
It can cause:
heavy periods
painful periods
pelvic heaviness
cramping
pain that worsens over time
Adenomyosis is more common in women in their 30s and 40s, but it can occur at other ages too.
4. Endometriosis
Endometriosis is a condition where tissue similar to the lining of the uterus grows outside the uterus.
It is often associated with pain, but some people also experience heavy bleeding.
Symptoms may include:
painful periods
pelvic pain
pain with sex
bowel or bladder symptoms around the period
fatigue
fertility concerns
heavy or irregular bleeding in some people
5. Uterine or cervical polyps
Polyps are small growths that can occur in the uterus or cervix. They are often benign, but they can cause abnormal bleeding.
Polyps may cause:
heavy periods
bleeding between periods
spotting
bleeding after sex
bleeding after menopause
Bleeding between periods or after sex should be discussed with a GP.
6. Thyroid problems
The thyroid helps regulate metabolism and can also affect the menstrual cycle.
An underactive or overactive thyroid may contribute to:
heavy periods
irregular periods
fatigue
weight changes
temperature sensitivity
mood changes
changes in hair or skin
A blood test can help check thyroid function.
7. Contraception changes
Some contraceptives can change bleeding patterns.
Heavy or irregular bleeding can occur with:
starting or stopping hormonal contraception
a copper intrauterine device
missed contraceptive pills
some long-acting contraceptive methods, especially in the early months
emergency contraception
A GP can help work out whether the bleeding pattern is expected, whether tests are needed, and whether another contraceptive option may suit you better.
8. Medications
Some medicines can contribute to heavier bleeding.
These may include:
blood thinners
some hormonal medications
some medications that affect clotting
some complementary or herbal products
Do not stop prescribed medication without medical advice. Your GP can help review whether medication may be contributing and whether changes are appropriate.
9. Pregnancy-related causes
Sometimes bleeding that seems like a heavy period may be related to pregnancy.
This can include:
early pregnancy bleeding
miscarriage
ectopic pregnancy
If there is any chance you could be pregnant and bleeding is heavy, painful, one-sided, or associated with dizziness or fainting, seek urgent medical care.
10. Bleeding disorders
Some people have a bleeding tendency that makes periods heavier.
This may be more likely if you:
have had heavy periods since your first period
bruise easily
have frequent nosebleeds
bleed heavily after dental work or surgery
have a family history of bleeding problems
Your GP may recommend blood tests or specialist referral if this is suspected.
11. Perimenopause
In the years leading up to menopause, hormones can fluctuate. This can cause changes in the timing, heaviness, and predictability of periods.
Although heavier or irregular bleeding can occur during perimenopause, it is still important to check symptoms, especially if bleeding is very heavy, prolonged, between periods, after sex, or occurs after menopause.
12. Less common but important causes
Less commonly, heavy or abnormal bleeding can be related to pre-cancerous changes or cancer of the uterus or cervix.
Most heavy periods are not caused by cancer, but certain bleeding patterns should always be assessed. These include:
bleeding after menopause
bleeding after sex
bleeding between periods
new heavy bleeding after age 45
persistent pelvic pain or unexplained weight loss
abnormal cervical screening results
bleeding that is unusual for you and does not settle
When should I see a GP about heavy periods?
You should book a GP appointment if:
your periods are affecting your work, exercise, sleep, travel, relationships, or social life
you need to change pads, tampons, period underwear, or cups very frequently
you pass large clots
you bleed for more than 7 days
your periods have suddenly become heavier
you feel tired, dizzy, faint, breathless, or unusually low in energy
you have pelvic pain
you bleed between periods
you bleed after sex
you might be pregnant
you are over 45 and your bleeding pattern has changed
you are worried about your period pattern
You do not need to wait until symptoms are severe. If your bleeding is affecting your quality of life, it is worth discussing.
What will a GP ask about?
A GP may ask about:
how often your periods come
how many days you bleed
how heavy the bleeding is
whether you pass clots
whether you flood or leak through clothing
whether you need to change protection overnight
whether you have pain
whether you bleed between periods or after sex
your contraception
pregnancy possibility
medications and supplements
cervical screening history
past pregnancies
family history
symptoms of low iron, thyroid disease, endometriosis, or bleeding disorders
It can help to bring notes from your last few cycles, including dates, heaviness, pain, clots, and any bleeding between periods.
What tests might be needed for heavy periods?
Tests depend on your age, symptoms, medical history, examination findings, and pregnancy possibility.
Your GP may recommend:
pregnancy test
full blood count to check for anaemia
iron studies or ferritin
thyroid function test
cervical screening test if due
STI testing if relevant
pelvic ultrasound
further hormonal tests in selected cases
referral to a gynaecologist if needed
Not everyone needs every test. The assessment should be tailored to your symptoms and risk factors.
How are heavy periods treated?
Treatment depends on the cause, your age, symptoms, medical history, contraception needs, pregnancy plans, and preferences.
Options may include:
iron replacement if iron is low
anti-inflammatory medication for some people
non-hormonal medication to reduce bleeding
hormonal contraception
hormonal intrauterine device
treatment of thyroid or other medical conditions
management of fibroids, polyps, adenomyosis, or endometriosis
referral to a gynaecologist for further assessment or procedures if needed
The aim is to reduce bleeding, improve quality of life, treat iron deficiency, and address any underlying cause.
Can heavy periods cause low iron?
Yes. Heavy periods are a common cause of iron deficiency and anaemia.
Symptoms of low iron or anaemia may include:
fatigue
weakness
dizziness
shortness of breath on exertion
headaches
poor concentration
restless legs
hair shedding
palpitations
If you have heavy periods and feel tired or run down, it is worth asking your GP whether blood tests are appropriate.
When should I seek urgent help?
Seek urgent medical care if you have:
very heavy bleeding that soaks through pads or tampons rapidly
bleeding with fainting, collapse, chest pain, or shortness of breath
severe pelvic or abdominal pain
one-sided pelvic pain with possible pregnancy
shoulder tip pain with possible pregnancy
heavy bleeding while pregnant
fever with pelvic pain
bleeding after menopause
symptoms that make you feel unsafe or seriously unwell
For severe symptoms, call 000 or attend the nearest emergency department.
Local GP care for heavy periods in Sydney’s eastern suburbs
If you live in Sydney’s eastern suburbs and are dealing with heavy periods, Dr Amanda Henderson can help assess what may be causing the bleeding and what to do next.
A GP appointment can help with:
understanding whether your bleeding pattern is normal or abnormal
checking for iron deficiency or anaemia
reviewing contraception and medications
assessing symptoms of fibroids, adenomyosis, endometriosis, thyroid disease, PCOS, and perimenopause
arranging blood tests or ultrasound if needed
discussing treatment options
organising referral to a gynaecologist if appropriate
Book a GP appointment for heavy periods
Heavy periods are common, but they should not be something you simply have to put up with.
If your periods are heavy, painful, prolonged, unpredictable, or affecting your life, consider booking an appointment with Dr Amanda Henderson to discuss your symptoms and next steps.
FAQs
What is the most common cause of heavy periods?
There is not one single cause for everyone. Common causes include hormonal changes, fibroids, adenomyosis, endometriosis, polyps, thyroid problems, contraception changes, medications, bleeding disorders and perimenopause.
How do I know if my period is too heavy?
Your period may be too heavy if you need to change protection very frequently, bleed through clothes or bedding, pass large clots, bleed for more than 7 days, feel exhausted or dizzy, or avoid normal activities because of bleeding.
Are heavy periods normal?
Heavy periods are common, but that does not mean they should be ignored. If bleeding affects your quality of life or causes low iron, it is worth seeing a GP.
Can fibroids cause heavy periods?
Yes. Fibroids can cause heavy or prolonged periods, pelvic pressure, bloating, and other symptoms. A pelvic ultrasound may be used to check for fibroids if they are suspected.
Can endometriosis cause heavy bleeding?
Endometriosis is more commonly associated with painful periods and pelvic pain, but some people with endometriosis also experience heavy or irregular bleeding.
Can heavy periods make me tired?
Yes. Heavy periods can lead to iron deficiency or anaemia, which may cause tiredness, dizziness, weakness, shortness of breath, headaches, and poor concentration.
Should I see a GP if my periods suddenly become heavier?
Yes. A sudden change in your bleeding pattern should be discussed with a GP, especially if you are over 45, could be pregnant, have pelvic pain, bleed between periods, or feel unwell.
What tests does a GP do for heavy periods?
A GP may recommend a pregnancy test, blood tests for anaemia and iron levels, thyroid testing, cervical screening if due, STI testing if relevant, or a pelvic ultrasound. The tests depend on your symptoms and medical history.
Can contraception help heavy periods?
Some forms of contraception can reduce heavy bleeding, while others may make bleeding heavier or more irregular. A GP can help review which option is most suitable for your health, symptoms, and pregnancy plans.
When is heavy bleeding an emergency?
Heavy bleeding may be urgent if you are soaking through protection rapidly, feel faint or short of breath, have severe pain, might be pregnant, or have bleeding after menopause. Seek urgent medical care if symptoms are severe.