Menstruation will only occur when a woman is not pregnant. When pregnant, women will not experience menstruation. Need to be aware of if there is bleeding through the vagina during pregnancy which is thought to be a sign of menstruation, even though it may actually be a sign of certain disorders in pregnancy. Some bleeding conditions that are similar to menstruation during pregnancy can be serious, although some are not. However, pregnant women should be aware of symptoms similar to menstruation. If it appears, you should immediately consult a doctor. Causes of Bleeding While Pregnant Causes of bleeding resembling menstruation during pregnancy, can be distinguished based on the period of pregnancy, namely: Early pregnancy Spotting of blood in early pregnancy is actually quite common, and usually only for a short period of time, around 1-2 days, with a small amount of bleeding. Generally only arise such as blood spots or brown spots on the underwear. This condition is known as ...