Ans. is d, i.e. Test maternal serum for rubella specific IgG and IgM antibodies immediately and after 3 weeks.Patient's immune status is not known. The first step in the management is to test maternal serum for rubella-specific IgG and IgM antibodies immediately to determine the immune status and after 3 weeks to detect the occurrence of infection. Presence of rubella-specific IgG antibodies in the initial serum sample indicates immunity. Presence of IgM antibodies in the first or second samples indicates acute infection with a high risk of congenital rubella.