What is the clinical presentation of placenta previa and how is the diagnosis made?
Bleeding associated with a placenta previa is not associ-ated with abdominal pain and may be sudden in onset. The amount of bleeding may range from very mild and inter-mittent to profuse and life-threatening.
Diagnosis is usually made by ultrasonic evaluation of the position of the placenta relative to the internal cervical os. If the diagnosis cannot be made by ultrasound then a vaginal examination will be performed in the operating room. The patient is brought to the operating room and prepared for emergency induction of general anesthesia and cesarean section in the event of profuse hemorrhage after vaginal examination. This is referred to as a “double set-up” (Table 61.4).