Symptoms of placenta previa include one or both of the following:

• Sudden, painless vaginal bleeding that ranges from slight to heavy. The blood is often bright red. Bleeding can occur as early as the 20th week of pregnancy but is most common during the third trimester.
• Symptoms of preterm labor. One in 5 women with signs of placenta previa also has uterine contractions.²

Bleeding from placenta previa may taper off and even stop for a while. But it nearly always starts again days or weeks later.

Some women with placenta previa do not have any symptoms. In this case, placenta previa may only be diagnosed by an ultrasound done for other reasons.