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Many women sometimes notice smaller or bigger blood clots during menstruation. It is perfectly normal to wonder whether this is normal and if it requires medical attention. Generally, blood clots are a normal occurrence but sometimes their dimensions and frequency can indicate a problem.

Understanding menstruation

Menstruation is an important and regular occurrence in every healthy woman’s life. Periods start during puberty and end in menopause. During these monthly cycles the uterus sheds its endometrial lining, which passes through the vagina. This happens because after the egg is created, it passes into the uterus and embeds into its lining. If it is not fertilized by sperms, the body expels it along with the lining, which results in menstrual bleeding.

Menstruation blood clots

Menstrual blood clots are in fact the body’s natural way to control the bleeding. When the blood pools inside the uterus, it may form clots. Blood that comes out bright red has been expelled quickly, while darker blood means that it stayed inside for longer.

Several factors play a role in determining whether there will be blood clots during menstrual bleeding. For example, larger uteruses tend to have more clots than smaller ones. The ability of myometrium to contract is another factor. Adenomyosis and fibroids, polyps and adhesions may also lead to formation of blood clots. If the cervix has a smaller diameter, the chance of clots increases.

The body produces and releases anticoagulants during menstruation to stop blood clotting. However, if the flow is particularly heavy, anticoagulants may not have enough time to work properly and there may be bright red or dark blood clots. The more clots there are, the thicker the flow will be. This usually happens during the days with the heaviest flow, and less often at the very beginning or at the end of menstrual bleeding.

During the last days of a period the flow may become darker, brown or even black. This is normal and it is the sign that older blood is being expelled. Blood turns darker because of oxidation.

Having occasional heavy or very heavy flows is normal, but if they occur every month and if they are so heavy that they prevent a woman from her normal activities, she should see a doctor in order to prevent complications like anemia, fatigue and weakness.

When to see a doctor regarding blood clots

If the blood clots are big, larger that a quarter, and, if they occur frequently during the day, it is recommended to see a doctor.

Blood clots during menstruation may also be a warning of a problematic pregnancy. Blood clots and lumps of gray tissue can happen after a miscarriage. Pregnant women who pass blood clots should see a doctor because they may be a sign of ectopic pregnancy, miscarriage or other pregnancy-related problems.

Particularly heavy periods and large and frequent blood clots may also be a sign of non-malignant uterine tumors.

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