Symptoms of placenta previa are typically bleeding, usually in the second and third trimester. Most women won't know they have a previa. It's found incidentally when they have their second trimester ultrasound. Typically, women will have a routine anatomy scan around 18 to 20 weeks, average is about 20 weeks. Often time, the placenta previa's diagnosed at that time. They notice the placenta's implanting lower by the cervix or covering the cervix. But the good news, the majority of those will become, or move out-of-the-way by late in the third trimester. So just because it's diagnosed incidentally on the ultrasound doesn't mean it's going to be there at the time of delivery. But most women will present, in terms of symptoms, will present second or third trimester with bleeding. Usually it's painless bleeding but bleeding itself from a previa will cause contractions, and so some women may present with contraction pain and possibly signs of preterm labor when in fact, it's actually a previa.
