Blood clots during menstruation: what to do?

Menstruation affects all pubescent women. However, every woman's menstrual cycle is different. Premenstrual syndrome, flow volume and viscosity vary according to the individual. When periods are thick, they can even take the form of blood clots. These impressive periods are often a cause forconcern. Rest assured, Elia explains all you need to know about blood clots during menstruation.

What are menstrual blood clots?

With their viscous appearance and dark red color, menstrual blood clots can quickly become a cause for concern. Often thought to be a menstrual disorder, the phenomenon is in fact quite normal, if not widespread. The onset of menstruation corresponds to the moment when the uterine mucous membrane detaches from the uterus and is evacuated when the ovum has not been fertilized. This mucous membrane, which is none other than the endometrium, is extremely vascularized. As it disintegrates, it causes bleeding. Menstrual blood clots sometimes look like pieces of flesh, but this is not the case. It's blood that can sometimes clump together to form a clot. During menstruation, pieces of mucous membrane can be evacuated.

What causes menstrual blood clots?

The body is trained to clot blood. When we cut ourselves, this slows down or even prevents bleeding. However, during menstruation, the blood must be thinned to be evacuated quickly. Women secrete a natural anticoagulant (plasmin) to prevent the formation of blood clots during menstruation. Sometimes this is not enough, as after a night's sleep. When lying down, blood is more difficult to evacuate. As it stagnates, it clumps together, then flows out in the form of a large blood clot in the period.

Heavy periods favour blood clots

Menstrual blood clots usually occur during the two days of heaviest flow. Moreover, heavy menstrual flow favors this phenomenon. Indeed, faced with a heavy flow, the body may show its limits or fail to secrete enough anticoagulant. As a result, menstrual blood clots appear more frequently.

Is it normal to have blood clots during menstruation?

It's perfectly normal to have blood clots during your period, especially after dark, as the flow has not been able to flow as freely. Similarly, a large blood clot during your period on the pill is nothing to worry about. Even if it's not a menstruation as such, the presence of blood causes coagulation.

However, you must remain vigilant, as menstrual blood clots can also be linked to iron deficiency (anemia). If you're experiencing this phenomenon for the first time, take a look at your diet. Are you eating enough lentils, kidney beans or meat? When blood clots during menstruation are accompanied by severe fatigue, dizziness or unusual shortness of breath, you should make an appointment to see your doctor. He or she will take a blood sample. If iron deficiency is confirmed, he or she will prescribe dietary supplements.

Finally, if you're menopausal or have bleeding with blood clots, consult your doctor, even if you're on hormone therapy.

Loss of flesh or mucous membrane

Women often describe menstrual blood clots as the loss of pieces of flesh, but this is not the case. During menstruation, pieces of poorly disintegrated mucous membrane can eventually mix with the clots. Their viscous but dark appearance makes them quite similar.

What is the usual size of blood clots?

Menstrual blood clots can vary in size from a few millimetres to several centimetres. Although not alarming, the repeated presence of a large blood clot in your period(over 2.5 cm) should prompt you to consult your doctor.

Is there a treatment for blood clots?

There is no treatment for menstrual blood clots, unless you are anemic. In the case of blood clots caused by heavy periods, oral contraception can reduce menstrual flow.

How can blood clots during menstruation be reduced or eliminated?

Certain foods and grandma's tricks can boost the body's ability to thin blood during menstruation:

  • Foods rich in omega-3 (fish, avocado, eggs, milk, almonds) ;
  • Infusion of nettle and thyme (rich in iron);
  • Sage infusion (rich in vitamin K, with strong anticoagulant properties);
  • Warm compress on lower abdomen when flow is heavy;
  • Food supplements to prevent iron deficiency.

Should I consult a doctor about blood clots?

Blood clots are nothing to be afraid of. However, there are times when a health specialist's intervention is necessary.


In the event of pregnancy, blood clots in the menstrual period are not necessarily a sign of miscarriage. However, you should consult your doctor as soon as possible to make sure everything's all right. In fact, even a blood flow without a clot should be the subject of a visit to the doctor.

Bleeding periods

Bleeding periods can be very uncomfortable. We use this term when the flow is heavy and lasts more than 7 days. The presence of blood clots in these periods, which are difficult to control with conventional sanitary protection, should also be a warning sign. Bleeding periods can be caused by :

  • A copper coil ;
  • An early miscarriage;
  • A polyp (small growth of flesh in the uterus);
  • A submucosal fibroid;
  • Adenomyosis (more common in women aged 40-50).

The FAQ of haemorrhagic periods

Are menstrual blood clots serious?

In most cases, blood clots during menstruation are not serious. Blood clots or loss of pieces of flesh are nothing to worry about, especially if they measure less than 2.5 cm. Beyond this size, seek professional advice. Similarly, if bleeding occurs during pregnancy or menopause, consult your doctor even if the discharge does not contain blood clots.

What causes menstrual blood clots?

Period blood clots appear when the flow is heaviest (one or two days). In this case, your body is unable to secrete enough natural anticoagulant to thin the menstrual fluid. A large blood clot in the period can also be seen in the morning, as the flow has more difficulty being evacuated at night and therefore coagulates. The heavier a woman's period, the more prone she may be to the phenomenon.

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