Miscarriage-About 20-30% of pregnancies end in miscarriage. Bleeding or spotting can be an early sign of miscarriage. Bleeding or spotting during pregnancy does not always mean that the woman will not go on to have a healthy pregnancy but it is reason for concern.A miscarriage often starts with light spotting that turns to heavy bleeding.wenty to twenty-five percent of women have bleeding or spotting during pregnancy. The bleeding is generally not as heavy a regular period. However, if a woman did not know that she was pregnant, she may assume the bleeding was just a light period.