The vast majority of women stop menstruating when they are pregnant. Some individual women who are physically strong may still menstruate after pregnancy, but pregnant women usually have no other symptoms.
Menstruation during pregnancy is usually low in volume and light in color. Sometimes pregnant women have miscarriages that can be mistaken for pregnancy periods, so they need to be identified.
Miscarriage usually has abdominal pain that is paroxysmal and bleeds bright red. Those with these characteristics are usually miscarriages, not pregnancy periods, because pregnancy periods do not feel uncomfortable.