Are blood clots normal during your period?
Yes, small clots are normal, especially on your heaviest days. They form when blood collects faster than your body's natural anticoagulants can thin it. Clots smaller than a quarter (about 2.5 cm) that come now and then are usually fine. Clots the size of a quarter or larger, or frequent clots with heavy bleeding, are worth checking with a doctor.
Why period clots form
As the uterine lining sheds, your body releases substances that keep period blood thin so it can flow out. On heavy days, blood can pool in the uterus or vagina faster than those substances work, so some of it clots. That's why clots are most common on days 1 and 2, in the morning after lying down, or when you stand up after sitting.
Normal clots vs ones to check
| Usually normal | Worth seeing a doctor |
|---|---|
| Smaller than a quarter (about 2.5 cm) | The size of a quarter or larger |
| Occasional, on heavy days | Frequent, through most of your period |
| Dark red or almost black | Come with soaking a pad or tampon every 1 to 2 hours |
| Period otherwise normal for you | New, with heavier or longer periods |
| No pain beyond usual cramps | Severe pain, or you feel tired, dizzy or breathless |
What can cause large or frequent clots
- Heavy menstrual bleeding from any cause: see why is my period so heavy.
- Fibroids or polyps, which can enlarge the uterus or block flow.
- Adenomyosis, which causes heavy, painful periods. See adenomyosis.
- Hormone changes, in teens, perimenopause, PCOS or after coming off birth control.
- Bleeding disorders, especially if heavy periods started with your first period.
- Miscarriage, if you could be pregnant: clots or tissue with cramping need prompt advice.
For the full symptom guide, see period blood clots. To check whether your periods count as heavy, try what counts as a heavy period.
Compare them to a coin (smaller or larger than a quarter), note which days they come, and how often you change protection on those days. Those three facts tell a doctor a lot.
See a doctor if you regularly pass clots the size of a quarter or bigger, soak through protection every 1 to 2 hours, bleed for more than 7 days, or feel tired, breathless or dizzy. Get urgent help if you could be pregnant and pass clots or tissue, or if you feel faint with heavy bleeding.
Frequently asked questions
Why are my period clots so big?
Large clots usually mean heavy flow. Common causes include fibroids, polyps, adenomyosis and hormone changes. It's worth a doctor's check.
Are period clots a sign of miscarriage?
Not if you're not pregnant. If you could be pregnant, clots or tissue with cramping need prompt medical advice.
Are jelly-like clots normal?
Small, jelly-like clots on heavy days are common. Frequent large ones aren't.
Do clots mean I'm losing too much blood?
Not always, but large frequent clots often go with heavy bleeding, which can lead to low iron.
Sources
- ACOG: Heavy Menstrual Bleeding
- Cleveland Clinic: Menorrhagia (heavy menstrual bleeding)
- NHS: Heavy periods
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
Period blood clots: what's normal and when to worrySmall period blood clots are normal. Why they form, what size is too big, how clots link to heavy periods and fibroids, and when to see a doctor.
What counts as a heavy period?What is a heavy period? Soaking a pad or tampon every 1 to 2 hours, clots bigger than a quarter, or bleeding over 7 days. A quick self-check.Why is my period so heavy? Common causes and what helpsWhy is my period so heavy? Fibroids, polyps, adenomyosis, hormone changes, an IUD or a bleeding disorder are common causes. What helps and when to get help.Heavy periods: what counts as heavy and what helpsHow to tell if you have heavy periods: soaking a pad every hour or two, clots, bleeding over 7 days. Causes, treatments that work, and when to get help.
Period calculator: when is my next period?Free period calculator: enter the first day of your last period and your cycle length to see your next 6 periods. Private, instant, nothing is stored.