Most menstrual clotting isn't dangerous or serious. It is important to take note of any changes in a menstrual period such as heavy bleeding and lower back pain, as well as clotting, however. These could be signs of a condition that requires medical treatment.
Menstrual clotting that occurs during pregnancy may be dangerous as it could indicate that the baby is growing outside rather than inside the uterus. Clotting and heavy blood flow could also signal a miscarriage or other pregnancy problems. If a pregnant woman is experiencing heavy bleeding and/or clotting, she should seek medical help immediately. Even if a woman who is experiencing these symptoms doesn't think she is pregnant, she is usually tested for pregnancy when a doctor is looking for the cause of the clotting.
Another common cause of heavy menstrual bleeding and clotting is uterine fibroids. Uterine fibroids are smooth muscle, non-cancerous tumors that grow in various parts of the uterus. Symptoms of uterine fibroids include back pain along with heavy bleeding and menstrual clotting. Doctors can conduct tests to check for the presence of fibroids.
Menstrual clotting can be a normal part of menstruation. Clots in the menstrual flow may simply mean that the blood is passing through the body at a fast pace. Some medications can cause changes in the menstrual flow that include clotting. This cause can be difficult to prove, but may be easier if a woman has recently started experiencing menstrual clots soon after starting a new medication.
Significant changes in weight — whether loss or gain — could also cause menstrual clotting. Clotting during menstruation can also be a normal part of peri-menopause, or the time before actual menopause occurs. Menopause is the end of menstrual periods for a woman, but in many cases, changes in blood flow may happen years before it occurs. Hormonal changes also cause clotting. If clotting as part of a menstrual period is something new for a woman, or if the clots are bigger than the size of quarters, she should get medical advice as soon as possible.
A woman who experiences any changes in her menstrual period that last more than a month, should report the change to her doctor. In most cases, menstrual clotting isn't dangerous, but when doctors know it's occurring, they can conduct tests to find the cause. Any other health concerns caused by the clotting or heavy periods should be addressed. For example, if a woman is losing a lot of blood through her menstrual flow, a doctor may prescribe iron supplements.