Final answer:
A nurse should monitor a client with suspected placenta previa for a large amount of bright red vaginal bleeding without pain.
Step-by-step explanation:
A nurse must monitor a client suspected of having placenta previa for a large amount of bright red vaginal bleeding without pain. Placenta previa occurs when the placenta implants in the lower part of the uterus, obstructing the cervical os. This condition typically presents with sudden, painless vaginal bleeding in the third trimester of pregnancy. It is important to note that severe abdominal pain with increasing fundal height is associated with abruptio placenta, not placenta previa.