Seek medical attention if your period lasts for more than a week, or if it is impacting your daily life. Your doctor will ask some questions to analyze your medical history and figure out what may be causing heavy periods with blood clots. He/she may also look at your cervix, uterus, anus, and vagina to look for unusual signs. If the physical examination or lab results do not provide an apparent reason for the heavy bleeding, the doctor may perform additional testing such as a hysteroscopy, using a microscope to look directly into the uterus lining to check for causes of the heavy bleeding.