An obsterician sees a pregnant patient who was exposed to rubella virus in the eighteen week of pregnancy. She does not remember getting a rubella vaccination. The best immediate course of action is to
High-Yield Explanation
The highest risk of fetal infection with rubella occurs during the first trimester. In seronegative patients, the risk of infection exceeds 90%. However, before other measures (such as termination of pregnancy) are considered, a rubella immune status must be performed. A rubella titer of 1:10 is protective.