As many as 30% of all pregnant women experience vaginal bleeding or spotting at some point during the pregnancy. This bleeding is most common during the first trimester, with causes ranging from miscarriage to harmless implantation bleeding.
Bleeding during pregnancy should always be reported to a healthcare practitioner, but second or third-trimester bleeding can be a first sign of some potentially serious pregnancy complications, such as:
Not all cases of mid to late pregnancy spotting will indicate problems, but it's particularly important to seek medical advice for later pregnancy bleeding. In addition to screening for pregnancy complications, the doctor may want to administer a RhoGAM shot to prevent Rh sensitization of Rh negative mothers.
Sources:
American College of Obstetricians and Gynecologists, "Bleeding During Pregnancy." Accessed 28 Jun 2008.
American Family Physician, "Late Pregnancy Bleeding." Apr 2007. Accessed 28 Jun 2008.
Signore, C.C., A.K. Sood, and D.S. Richards, "Second-trimester vaginal bleeding: correlation of ultrasonographic findings with perinatal outcome." American Journal of Obstetrics and Gynecology Feb 1998. Accessed 29 Jun 2008.
