Bleeding in Pregnancy
Bleeding is never normal, during pregnancy, but it is not always associated with a negative outcome. Many women will have some bleeding between finding out they are pregnant and going into labor. Here is a list of common reasons for bleeding during pregnancy, based on weeks of gestation.
From Getting Pregnant to 13 Weeks
Bleeding is common. Sometimes the cervix can bleed, like a nose bleed: messy, scary, but not dangerous. Sometimes bleeding is a sign of miscarriage. Some bleeding at this time in pregnancy is from a subchorionic hemorrhage (SCH). One way to understand SCH is like a loose placental edge. There is bleeding from the edge of the placenta. The result can be bright or darker bleeding, a little or a little more. It usually not heavy. There is no treatment for SCH. We are stuck with a wait-and-see approach. SCH can lead to miscarriage, but usually not. Cervix infection, causing irritation, can also cause bleeding.
From 13 Weeks to 22 Weeks
The same reasons for bleeding in the first 13 weeks of pregnancy can cause bleeding after 13 weeks, too. The cervix can still bleed, although less commonly. Bleeding from the subchorionic hematoma is usually dark, and is old blood, rather than new bleeding. NEW onset vaginal bleeding at this time in pregnancy should be evaluated with examination, including a speculum exam to see, and fingers to feel. Bleeding can be from the cervix opening up too soon.
From 22 Weeks to 34 Weeks
Cervix infection and irritation can cause bleeding at any time in pregnancy. More concerning is bleeding from placenta previa or the early onset of labor. Most patients will know about a low placenta from the ultrasound done at 20 weeks. Labor, or cervix dilation, can only be diagnosed by examination, best with finger exam of the cervix, sometimes by ultrasound. Bleeding with pain is most commonly from labor, but can also be caused by early detachment of the placenta, called abruption. Placental abruption usually has heavier bleeding, more pain, and more constant pain. Bleeding from placenta previa is usually painless. In all cases of bleeding at this time in pregnancy, urgent evaluation is best.
Between 34 and 37 Weeks
The most common cause of bleeding at this time in pregnancy is Premature Labor. As the cervix gets ready for labor, as it dilates, it can bleed. The dilation causes a mucousy discharge, which can be tinged red or brown, depending on how fresh the blood is. If the water bag breaks as the cervix dilates, fluid coming from the vagina can be red, mimicking heavy bleeding. We rarely stop a labor which starts after 34 weeks. Many babies born at this time in pregnancy will need extra medical attention at birth, so hospital evaluation is best. Placenta previa and placental abruption can also cause bleeding at this time.
After 37 Weeks
The most common cause of bleeding at this time in pregnancy is labor. The bleeding can be like the onset of a period. Light bleeding, without pain, can be managed just like the onset of labor. Heavier bleeding can still be labor, but patients should go in for evaluation sooner.
The Bottom Line
Vaginal bleeding in pregnancy needs to be evaluated and explained. Pregnant patients with vaginal bleeding need to be seen, to confirm baby’s well being and checked for cervix dilation.