Blood clots are generally normal during menstrual cycles, although at times it could indicate an issue, claims WebMD. On days when menstruating is the heaviest, clots are more likely to occur due to blood expelling rapidly, preventing anticoagulants from keeping the blood unclotted.
Clotting is not normal if there is a large amount of it, or if it is occurring over a long period of time. Blood clotting could indicate pregnancy and hormonal changes, chronic illness, fibroids, peri-menopausal changes and adenomyosis, according to the Center for Endometriosis Care.
If a menstrual cycle seems heavier than usual, and large or continuous blood clots occur in a small amount of time, it is necessary to seek medical attention to check for underlying issues, says Mayo Clinic.