Placenta previa is diagnosed through ultrasound, either during a routine prenatal appointment or after an episode of vaginal bleeding. Most cases of placenta previa are diagnosed during a second trimester ultrasound exam.
Diagnosis might require a combination of abdominal ultrasound and transvaginal ultrasound, which is done with a wandlike device placed inside your vagina. Your health care provider will take care with the position of the transducer in your vagina so as not to disrupt the placenta or cause bleeding.
If your health care provider suspects placenta previa, he or she will avoid routine vaginal exams to reduce the risk of heavy bleeding. You might need additional ultrasounds to check the location of your placenta during your pregnancy to see if placenta previa resolves.