During pregnancy, the appearance of dark red discharge can be caused by several conditions: the dark red discharge that appears in early pregnancy is mostly due to preterm miscarriage. Because the fetus is less stable at this stage, it is the peak time for miscarriage to occur; dark red discharge that appears in the middle of pregnancy is mostly related to placental factors, such as low lying placenta and placenta praevia, and these conditions require hospitalization. The dark red discharge that appears in late pregnancy is considered to be vaginal redness, which is a more accurate indicator of the onset of labor. The vast majority of pregnant women will go into labor spontaneously within 48 hours after the redness is stilled.