Period Blood Clots: What Causes Blood Clots During Period?

period blood clots during period

Last updated on July 28th, 2018 at 04:51 am

Do you have period blood clots that are dark colored? Are you feeling weak because of your prolonged periods? Do you have blood clots during periods for more than 24 hours? Do you change your sanitary pad frequently more than normal?

This article will explain whats normal about blood clots you see during your period and when its abnormal.


What causes period (Menstruation)?

Period, experienced by women, is due to breakdown of endometrium covering your womb. It is usually due to hormonal changes that occur during your menstrual cycle.

How long do period last? Normal period may last between 2 —7 days and may get lighter as it ends

What causes period to come out? Your period cycle (Menstrual cycle) is the difference between 2 periods. The first period day is the first day of your menstrual cycle. During your period, FSH (Follicle stimulating hormone) will stimulate your ovaries to start follicle development. As these follicle grows, they produce estrogen

What does estrogen do? After day 7 of your period, there is a thin layer of endometrium covering your womb. Estrogen will cause proliferation of endometrial cells to build up your endometrium should you get pregnant.

Also, rising estrogen level will stimulate the pituitary gland to cause LH surge. LH surge occurs 12 — 36 hours before your ovulation. After ovulation, estrogen level decreases with an increase in progesterone hormone

What does progesterone hormone do? Dominant progesterone and estrogen will continue to stimulate the endometrial glands to become more tortuous and prepare for implantation.

After intercourse and release of sperm during your fertile period, fertilization occurs and the baby (zygote) will be implanted into this endometrium. If implantation occurs, you may experience slight bleeding or spotting before period. If implantation does not occur, the endometrium will brake down forming period.


What causes blood clots during period?

These are the reasons you may have period blood clots.

Normal period

Early in your period, there is a rapid breakdown of the endometrium that comes out as clots. This does not last for more that 24 to 36 hours. This is because fibrinolysin help breakdown clots in your period.

During a heavy menstrual flow, if the endometrium is broken down very fast, fibrinolysin will not have enough time to break clots down. This comes out as blood clots.

If your blood clots are persistent for days with heavy bleeding, then its abnormal.

Uterine fibroid

These are growth in the uterus or womb in women that can cause blood clots during period. They commonly occur in women after the age of 30. Cause of fibroid is still not clear, though it is believed that there is a strong familial link. If your mother or your sister were diagnosed with fibroid, then there is a possibility that you may have fibroid. Also, fibroid is common in young women due to estrogen hormone. After menopause or during perimenopause, it shrinks in women.

There are different types of fibroid. The submucous type is the commonest cause of very severe bleeding in women. It is fibroid growth just beneath the endometrium. Other types of fibroids are the intramural type (Fibroid that grows within the uterine muscle), subserous type (grows outside the uterus) and the cervical fibroid.

What are the symptoms of fibroid

  • Heavy prolonged periods that are more than 7 days
  • Period blood clots
  • Frequent changing of your pads
  • Body weakness from anemia
  • Huge fibroid can cause abdominal swelling and obstructive symptoms like difficulty in passing urine or stool

Can fibroid be treated? If you have heavy excessive bleeding with clots, these are some medications that could help

  • Mefenamic acid
  • Tranexamic acid
  • GnRH agonist

Surgical options are

  • Myomectomy (Surgical removal of the fibroid)
  • Hysterectomy (Surgical removal of the uterus)
  • Fibroid Polyp removal

Endometrial thickening (hyperplasia)

Endometrial thickening can occur in women due to hormone imbalance. Women with PCOS (polycystic ovarian syndrome) with high estrogen level can cause proliferation and thickening of the endometrium. This thickening can come out as blot clots and be excessive.

What are the symptoms of endometrial hyperplasia?

  • Prolonged bleeding with blood clots during period
  • Short menstrual cycles
  • Vaginal bleeding in women that are more than 40 years
  • Infertility

Who can have endometrial hyperplasia?

  • Women more than 35 years
  • Nulliparous women (Women that has never been pregnant before)
  • Smoking
  • After menopause

You will need to inform your doctor and start a progesterone pill to normalize your period. If you are already taking estrogen replacement, then you will need progesterone too.

Vaginal infections in women

If you have infection down there at your vagina, then it may cause blood clots in period.

What are vaginal infection symptoms?

Abnormal discharge like greenish yellowish discharge, yellowish smelly discharge or thick white discharge with odor are symptoms of vaginal infections. Others are vaginal itching, vulva sore, fever, abdominal pain and body weakness.

You should inform your doctor if you have these symptom. Vaginal discharge samples are collected and tested for the cause. Treatment with antibiotics will follow after testing your blood and vaginal discharge with good success rate.

Endometriosis and Adenomyosis

Adenomyosis and endometriosis in women can cause heavy prolonged bleeding with blood clots.

What is endometriosis? This is abnormal growth of the endometrium outside the uterus. Endometrial tissues can be found in the ovaries, fallopian tubes, abdomen and other parts of the body.

Symptoms of endometriosis are

  • Severe pelvic pain
  • Painful periods or cramping
  • Painful sexual intercourse
  • Period blood clots

What is adenomyosis? This is presence of endometrial tissues within the uterus. If you’ve had an abortion with curettage or delivered by cesarean section, then it may be the cause of your heavy blood clots during period.

Symptoms of adenomyosis are:

  • Severe low abdomen pain
  • Heavy menstruation
  • Painful periods
  • Infertility
  • Pain during sexual intercourse

Adenomyosis can be treated with ibuprofen, hormonal IUDs and contraceptives. However, the definite treatment is removal of the uterus.

Endometriosis can be treated with hormonal contraceptive and ibuprofen. There is no known cure to the disease.

Endometrial cancer

If you are above 40 years and having period blood clots then it could be due to endometrial cancer or thickening. Most women that have cancer complain of heavy irregular periods or bleeding. However, some women may experience clear vaginal discharge, painful sexual intercourse and discomfort while urinating.

How can cancer be diagnosed?

If cancer of the endometrium is suspected, your doctor will take samples of uterine tissue for testing. This is endometrial biopsy. If your cancer is still in early stages, it can be treated and cured. Always inform your doctor of bleeding if you are above 40 or in menopause.

I have blood clots on period, how do i stop it?

Most women with blood clots during day 1 or 2 of your period may be normal. However, if your bleeding is more than 7 days and you have large blood clots, then its abnormal. Heavy period with clots can be contained with a menstrual cup. Though women use pads and tampons during heavy bleeding, it cannot absorb blood clots.

In addition, if your period continues more than 7 days with blood clots, you should let your doctor know.


FAQs about period blood clots in women

These are some frequently asked questions about blood clots during period. Let us know if you have any questions.

Is it normal to have blood clots during period?

Yes. During the early stages of your period you may experience severe increase bleeding with blood clots. These subsides in few days. A menstrual cup can help with heavy clots during periods.

Other causes of causes of blood clots in period are vaginal infection, endometrial thickening or cancer. You should inform your doctor if period bleeding is more than 7 days.

Is blood clots during period miscarriage?

If you are pregnant and having spotting, then blood clots can be due to miscarriage. Other causes of bleeding while pregnant are ectopic pregnancy, infections or spotting during implantation.

What causes blood clots during period with pain?

If you have prolonged periods and pain, then it may be due to an infection, endometriosis, adenomyosis or a sign of dysmenorrhea. Both adenomyosis and endometriosis can cause period blood clots with pain. However, this can be relieved with analgesics like ibuprofen or naproxen. If you have an infection, then antibiotics and pain relief drugs will help.

What does big blood clots in period mean?

Blood clots in period may not always be a problem, especially during the first days of menstruation. However, big clots in period is abnormal. During normal period, blood loss is less than 80mls. If you have prolonged periods with big blood clots then you should see your doctor immediately.

Possible causes are

  • Fibroid
  • Endometrial thickening
  • Cancer

Learn more: Causes of fibroid and treatment

What causes blood clots during period bigger than a quarter?

If you have period blood clots larger than a quarter, then you should inform your doctor. Its likely due to a medical problem like submucous fibroid, cervical polyps or endometrial hyperplasia. Further test may help confirm the cause.

What causes Large blood clots on period?

If you persistently have large blood clots on period then it may be due to any of these causes

  • Vaginal infection
  • Uterine fibroid
  • Endometrial thickening
  • Smoking
  • Cancer
  • Age more than 35 years
  • Endometriosis
  • Adenomyosis

What should i do? Inform your doctor. If its too heavy Get a menstrual cup.

Blood clots in my period, is it bad?

No and Yes. Blood clots in period is normal especially when it subsides in few days after your period starts. Very huge blog clots during period is abnormal and may mean there is a problem. Get your doctor inform about your symptoms.

Very large blood clots, is it normal sometimes?

No. If you experience very large blood clots during your period, then you should book an appointment with your doctor. Very large blood clots may be due to

  • Fibroid if less than 40 years
  • Cancer or endometrial thickening if you are more than 40 years


Now its your turn. Do you have prolonged bleeding with clots? Let us know if we can help.

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  • precious Reply

    Am having heavy period and clotting. Today is the 8th day. Though i had urinary tract infection some months back. Please can it be the infection or something else. I dild not abort nor am i pregnant. And the blood is light. I dont have any cramps or any pain. Just heavy flow anf cloting. Am still young please. Am just 19. Pls help me!!!

    • Dr. Dunn A. Reply

      Not normal to have heavy periods. talk to your doctor to know why its happening.

  • JOYCE Abhijeet Reply

    Dr. Since 2 months I bleeding, in February it was more later at March just few drops, and in between stopped for few days say one week , then again now in April it’s bleeding, it’s fresh blood orange colour, slight blood clot in a month one day clots very few.
    I visited doctor she gave me Sysron tablets and e tone tablets.. Still my bleeding has not stopped, one day no bleed next day can see few drops. M aged 50 yrs Now.
    Please help me to know. In 2015 I got papsmear done, it was normal this year I didn’t do it. Pls Dr help me to know my poblm
    Thanks lot in advance.

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