<Tr> <Td> Too - frequent periods (defined as more frequently than every 21 days) </Td> <Td> Polymenorrhea </Td> </Tr> <Tr> <Td> Extremely heavy or long periods (one guideline is soaking a sanitary napkin or tampon every hour or so, or menstruating for longer than 7 days) </Td> <Td> Hypermenorrhea </Td> </Tr> <Tr> <Td> Extremely painful periods </Td> <Td> Dysmenorrhea </Td> </Tr> <Tr> <Td> Breakthrough bleeding (also called spotting) between periods; normal in many females </Td> <Td> Metrorrhagia </Td> </Tr>

Where does the blood from the menstruation come from