This happens when mother contracts rubella during her pregnancy. the foetus is especially vulnerable during the first trimester, as it is during this time that the organs are being formed.
The classical features of congenital rubella were first described by Gregg in Australia in 1941, before the virus itself had been isolated and studied.
Rubella causes malformations via a primary effect on blood vessels in developing organs and by directly inhibiting mitosis, leading to reduced number of cells and a small sized rubella baby.
effects of congenital rubella:
brain - small brain size, mental retardation
eye - cataract, micropthalmia
ear - hearing defect
heart - patent ductus arteriosus, patent intraventricular septum
liver, spleen - hepatosplenomegaly, thrombocytopenic purpura, anaemia
general - low birth weight, failure to thrive, increased infant mortality
Treatment and management
There is no treatment. the baby sheds rubella virus and remains infectious for several months.
Congenital rubella is completely preventable by vaccination with live attenuated virus vaccine. This is now a routine childhood immunization, usually with the MMR vaccine. Pregnancy is a contra-indication to vaccination. This is an interesting example of a vaccine that is given to protect an as yet unborn, non-existent individual (the future foetus), as rubella itself is usually only a mild infection.
until effective vaccines were available in the 1960s, rubella was an important cause of congenital heart disease, deafness, blindness and mental retardation.