Which statement about rubella immunity during pregnancy is correct?

Which statement about rubella immunity during pregnancy is correct?

• A. If rubella IgG is negative, the mother is immune and the fetus is not at risk.
• B. If rubella IgG is positive, the mother is immune and the fetus is not at risk.
• C. If rubella IgM is positive, immunity is present.
• D. If rubella IgG is positive, you should delay pregnancy.

Answer: (C)

Understanding rubella serology in pregnancy is about what the antibodies tell you. Rubella IgG positivity means the mother has immunity from a past infection or vaccination, so she’s protected and the fetus is not at risk for congenital rubella from a new infection. Rubella IgM positivity, on the other hand, indicates a recent or current infection; this is the scenario that poses a real risk to the fetus, especially if it occurs in the first trimester, and requires careful monitoring and counseling. So, immunity is indicated by IgG positivity, not IgM. An IgM-positive result signals active infection rather than protection. The statement that IgM positivity equates to immunity is not correct.

Understanding rubella serology in pregnancy is about what the antibodies tell you. Rubella IgG positivity means the mother has immunity from a past infection or vaccination, so she’s protected and the fetus is not at risk for congenital rubella from a new infection. Rubella IgM positivity, on the other hand, indicates a recent or current infection; this is the scenario that poses a real risk to the fetus, especially if it occurs in the first trimester, and requires careful monitoring and counseling.

So, immunity is indicated by IgG positivity, not IgM. An IgM-positive result signals active infection rather than protection. The statement that IgM positivity equates to immunity is not correct.