According to the American Pregnancy Association, some bleeding during the first trimester is normal and happens to nearly 30 percent of all pregnant women. This bleeding, usually referred to as “spotting,” is generally very light in flow and brown or pinkish in color. Pregnancy-related bleeding is often the result of implantation, irritation or infection, or the onset of labor. With the exception of full-term labor, bleeding during the second and third trimesters is not considered a normal event.
Many women will discover a small amount of blood in their undergarments, usually within 2 weeks of conception and generally before they even realize they are pregnant. This is called implantation bleeding and is a normal side effect of the fertilized egg attaching itself to the wall of the uterus. Implantation bleeding is different for every woman; some might notice a light spotting for only a day while others will notice it for a few.
Irritation or Infection
Because the cervix is so sensitive during pregnancy, some women might experience light bleeding after sexual intercourse. Likewise, a pelvic or urinary-tract infection might also cause spotting. While these instances of bleeding aren’t usually a cause for concern, a pregnant woman should notify her caregiver right away so she can be properly evaluated and treated for any infection. Additionally, the caregiver might recommend that sexual intercourse be stopped until the spotting ceases.
Onset of Labor
It’s also normal for pregnant women to experience a small amount of bleeding just prior to the onset of labor. Usually, this occurs at the time she loses the mucus plug. A mucus plug is an accumulation of mucus-like fluid at the opening of the cervix that acts as a barrier between the outside world and the developing fetus. The mucus plug prevents harmful bacteria from entering the womb and causing infection.
A woman who notices bleeding during her pregnancy should wear a sanitary napkin to monitor the color as well as the duration and amount of blood flow. Although spotting is normal during the first trimester of pregnancy and at the onset of labor, soaking through a sanitary napkin within the course of an hour is not. Physicians also advise against inserting tampons, as they can introduce harmful bacteria and prevent a woman from properly monitoring her condition.
Regardless of the amount or duration of blood flow, a pregnant woman who experiences bleeding should call her caregiver for an immediate evaluation. Bleeding during the second and third trimesters, especially when accompanied by abdominal pain, is not normal and should be addressed as soon as possible. If possible, the soiled undergarments or sanitary napkin should be kept and shown to the caregiver during evaluation.