What causes bleeding in the third trimester?

Multiple. Placental abruption, placenta previa , local lesions and unidentified cause, are the commonest reason behind bleeding in the third trimester.
Variety of causes. First of all consider calling your OB about bleeding while pregnant. The most common reason is a recent office exam or sex. Concerning reasons include preterm labor, abruption, placenta previa and vasa previa. Its always a good idea to call your OB and discuss bleeding and i would do it as soon as possible.

Related Questions

Can bleeding in the third trimester affect my baby?

Needs evaluation. Bleeding during pregnancy should always be investigated. In the third trimester, causes may be non harmful cervical changes to more concerning placental issues. Their effect on the baby really depends entirely in the cause. If it is noted after sex, and it is light, it may just be due to cervical irritation. That is ususally ok. Heavier bleeding requires an ultrasound and/or blood tests. Visit ob. Read more...
Yes. Placenta previa/accreta or placental abruption can cause preterm birth, fetal death and maternal hemorrhage. Go to the emergency room for any vaginal bleeding in the third trimester (or any other pregnancy time, for that matter). Read more...
Yes. Vaginal bleeding in the third trimester is never normal and always requires immediate evaluation by a doctor. There are many different causes that only a physical exam can detect. Bleeding can be from the placenta, which is the nutrition source for your baby. Read more...

How many women bleed during the third trimester?

Not too many. I would get some attention on that one. It could be your cervix changing but more worrisome is bleeding from the placenta compromising fetal oxygen. Some spotting after intercourse isn't unusual but third trimester bleeding is nothing to blow off. Read more...