QUESTION My 22-year-old patient immigrated to Canada 6 years ago from a cou
ntry where there are no routine immunizations. She is now at 10 weeks' gest
ation and was exposed to a child with rubella infection. Her immune status
is unknown. Should I give her passive or active immunization? How should I
follow her pregnancy? And what should I tell her about the risk for her fet
us?
ANSWER If the exposure took place less than 1 week ago, blood should be sen
t for rubella antibody titre. If results are positive for IgG, she is immun
e and there is no risk for the fetus. If a patient's immune status is unkno
wn and the time of exposure is uncertain, serum samples for rubella antibod
ies should be obtained 3 weeks apart. Detection of rubella-specific IgM in
a sample will confirm recent infection. Your patient should be counseled ab
out the potential risk for her fetus and referred to a high-risk pregnancy
clinic for follow up. If seroconversion does not take place, she requires i
mmunization immediately postpartum before discharge from hospital.