Many women have this symptom within a week or two of their pregnancy. Light bleeding (spotting) might occur 8–10 days following ovulation. It normally occurs around the time she would have had her monthly cycle. Some women mistakenly believe they have begun their period when, in reality, they are pregnant. This condition is called "overestimating." Other women may not be aware they are pregnant until they see blood on their underwear. The amount of blood that can be seen without using a sanitary pad or tampon is known as "dark blood." You should seek medical advice if you are experiencing dark blood between menstrual periods or after it has occurred. It is important to recognize the difference between normal spotting and abnormal bleeding. Abnormal bleeding is usually pain or cramping associated with bleeding from several sites at once, heavy blood loss, or lack of control over the amount of blood lost. If you experience abnormal bleeding, you should contact your doctor immediately so that an assessment can be made as to whether or not an examination is needed. Normal spotting is usually very light and occurs only during certain phases of your pregnancy. It will vary in duration but generally lasts for about 3 weeks. As your pregnancy progresses, the amount of blood shed through menstruation decreases. By the end of the first trimester, most women will experience only minimal bleeding through their fingers during their periods. By the end of the second trimester, most women report no bleeding at all.