Spotting a blood clot within the blood expelled during a normal menstrual cycle can be worrying, but in many cases the occasional clot is a perfectly normal occurrence. The seriousness of a blood clot found in the menstrual blood depends on the normal physiology of the woman, accompanying symptoms and whether or not the clotting is causing other problems, such as anemia.
Physiology
Blood clots form in the body when blood collects and tiny blood cells called platelets join together to form a clump. Blood normally exits the uterus fairly quickly during menstruation. However, if the blood flow is slow and blood pools in the uterus, a clot may form from this old blood along with other cells from the uterus and endometrium.
Normal Clotting
In some women, clotting is a normal part of menstruation. If a woman's blood flow is naturally faster than the uterus' ability to clear it out, clots may occur during most menstrual periods and do not indicate a problem. The natural diameter of the cervix and the strength of uterine contractions during menses are the main factors at play for women who clot naturally during their periods.
Abnormal Clotting
Abnormal clotting occurs when the clots are caused not by a woman's natural biology, but by other factors. These can include fibroids in the uterus or polyps on the uterus or cervix, both abnormal growths that can block the efficient flow of blood. Hormonal changes stemming from perimenopause or medications sometimes bring about blood clots in menstrual blood. A large uterus, which can develop after childbirth, may encourage pooling of blood and lead to clots. Pregnancy may be another cause of clots and can be a sign of an early miscarriage even before the woman is aware that she was pregnant.
Diagnosis
To diagnose the underlying cause of blood clots during menstruation, a doctor may take a blood sample to look at hemoglobin levels. According to Obgyn.net, this hematocrit measurement is the most important measure for determining whether or not the clots are dangerous or harmless. Typically, if the blood count remains normal and the woman does not develop anemia and the clotting does not occur outside of the woman's normal menstrual period, the clots are considered normal for her. If the clotting appears abnormal, the doctor may perform a Pap smear or ultrasound to determine the specific cause.
Warnings
If blood clots are accompanied by excessive bleeding, defined as soaking a pad or tampon every hour for a few hours or more, this can be a sign of a serious disorder called endometriosis and should be reported to a doctor. In endometriosis, the endometrial tissue grows outside of the uterus instead of remaining confined within it.
