Rubella, or German measles, is a communicable RNA virus whose effects, including rash and fever, are generally mild when contracted in later childhood or adulthood. However, if contracted by a pregnant woman, rubella may cross the placental barrier and cause fetal death or serious deformities in her offspring. A congenital maternal infection, it is a member of the STORCH complex (syphilis, toxiplasmosis, varicella and other infections, rubella, cytomegalovirus, and herpes), a group of maternal infections that have similar effects on offspring. A complex of effects, fetal rubella syndrome (FRS) or congenital rubella syndrome affects about 85% of offspring whose mothers contracted rubella during the first 20 weeks of pregnancy. Effects are greatest in offspring exposed to rubella during the embryonic period, although visual and auditory defects may occur with exposure up to 20 weeks gestation (Centers for Disease Control and Prevention, 2001).
Varicella, or chicken pox, is an infection that if contracted by a pregnant woman may cross the placental barrier and cause serious deformities in her offspring. A congenital maternal infection, it is a member of the STORCH complex (syphilis, toxiplasmosis, varicella and other infections, rubella, cytomegalovirus, and herpes), a group of maternal infections that have similar effects on offspring. An estimated 1-2% of offspring of mothers who contract varicella 8-20 weeks post-conception show some aspects of the syndrome, and about 50% of those die in early infancy. The number and variety of defects that may be shown is large, and the range of effects is highly variable. Even basic characteristics will not appear in all cases (National Organization for Rare Disorders, 1997).