Causes of Spotting in Late Pregnancy

•Preterm labor- Spotting during late pregnancy can be a symptom of preterm labor. Preterm labor can happen quickly so it is important to spot the symptoms early. Symptoms of preterm labor include bleeding, menstrual like cramping, backache, changes in vaginal discharge, leaking fluids, or an increase in pelvic pressure. If you have had spotting later in your pregnancy or have symptoms of preterm labor call your doctor right away.

•Placental abruption - Bleeding after the twentieth week of pregnancy can be due to a problem with your placenta. The placenta is attached to the uterine wall. If the placenta begins to separate from the uterus, you may have bleeding. This is called a placental abruption. It can cause the baby to be deprived of oxygen and nutrients that it receives from the placenta.

•Placenta previa is one of the most common causes of bleeding during the third trimester. During a normal pregnancy the placenta attaches to the upper portion of the uterus. With placenta previa, the placenta attaches to the lower section of the uterus. The lower section is weaker and full of tiny blood vessels. As your uterus stretches some of these tiny vessels may burst and cause bleeding. Placenta previa can be dangerous to baby and mom. Complications include hemorrhaging, placental abruption, preterm labor, or anemia.
Other causes of spotting during pregnancy

•Spotting after sex- Sometimes sex can cause spotting during pregnancy. If your cervix has been irritated from having sex, you might notice a little spotting afterwards. You should let your doctor know if you have had intercourse before you noticed spotting.

•Start of labor- Normal labor may start with light spotting. This is sometimes known as having a bloody show. If you are at the end of your pregnancy, and notice a pink, red or brown discharge you may be starting labor.

•Hemorrhoids- This might sound silly but many women have mistaken a small bleed from a hemorrhoid with vaginal bleeding. If you are not sure you are better off calling your doctor or midwife just to be safe.

•Internal exams- You may have some spotting after having an internal exam. During pregnancy you have an increased blood supply to the cervix. Any irritation of the cervix might cause a little spotting.
 
article cited on http://www.justmommies.com/