Which assignment should be avoided by a nurse who is pregnant?

In considering the assignments for a nurse who is pregnant, it is essential to focus on potential exposure to infectious diseases that could pose risks to both the nurse and the developing fetus. Parvovirus B-19, which is mentioned in the scenario, is particularly relevant because it can cause an illness known as fifth disease. While it is usually mild in children, the infection can have serious consequences in pregnant women, including the risk of fetal anemia or even miscarriage.

Therefore, caring for a 9-year-old client with reported parvovirus B-19 should be avoided by a pregnant nurse due to these potential health risks. The other options involve clients with various conditions that do not pose the same level of risk regarding infectious diseases that could affect a pregnant nurse and her unborn child.