Women's Health Community

Dear An: A period with big clots usually reflects a heavier than usual flow. There is an enzyme produced by the lining of the uterus designed to keep menstrual blood from clotting. This allows the menstrual fluid to more readily pass out of the tiny cervical canal and into the vagina. When a woman is bleeding very heavily during her period the amount of flow surpasses the amount of enzyme--thus leading to passage of large clots. However, the action of this enzyme is localized to the inside of the uterus so it should not have anything to do with inability of other blood to clot.

More cramping can also be linked to a heavier than usual flow. Cramping can come from either passage of the large clots and/or from an increased amount of prostaglandins (substance that creates painful contractions of the uterus).

One cause of a heavier than usual flow is a thicker than usual lining inside the uterus. Occasionally most of us will have a heavier (or lighter flow) than normal. Most commonly this is from a temporary change in hormone levels. If you are sexually active, an undetected pregnancy/miscarriage can also bring a heavy flow. A reliable pregnancy test can be done if needed.

Bottom line, if the severe cramping, large clots, or a heavy flow persists you should contact your GYN or MD. Even your local county family planning clinic can do a basic exam. Hopefully this was just an isolated incident and your own "normal for you" flows will return next month.

Yours,
Jane