Rubella, also known as the German Measles, is a viral illness. If the infection occurs during pregnancy, it can result in what is known as congenital rubella syndrome (CRS). Women in their first trimester of pregnancy are at greatest risk of developing a viremia and congenital birth defects from this illness. Congenital rubella syndrome is characterized by abnormalities including heart defects, deafness, and cataracts. (1) Other common abnormalities seen in the newborn are thrombocytopenia and encephalitis.
The CDC has defined congenital rubella syndrome as any two complications from List #1 or one complication from list #1 and one complication from list #2. (2)
List #1- Cataracts or congenital glaucoma, congenital heart disease, pigmentary retinopathy, loss of hearing
List #2- Purpura, splenomegaly, jaundice (onset within 24 hours of birth), microcephaly, mental retardation, meningoencephalitis, radiolucent bone disease
Although there have been no congenital defects reported after rubella vaccine administration, the theoretical risk does exist and therefore the use of this vaccine in pregnancy is contraindicated. It is advised that women avoid getting pregnant for 3 months after receiving the vaccine. If a women were to become pregnant shortly after receiving the vaccine, the risk is very small and almost non existent and therefore it is not indicated for such women to terminate their pregnancies. (2)
References:
1. Oster ME, Riehle-Colarusso T, Correa A. An update on cardiovascular malformations in congenital rubella syndrome. Birth Defects Res A Clin Mol Teratol. Jan;88(1):1-8.
2. Briggs G, Freeman R, Yaffe S. A Reference Guide to Fetal and Neonatal Risk: Drugs in Pregnancy and Lactation. Vol 1. Seventh Edition ed. Philadelphia, PA: Lippincott Williams & Williams; 2005.
