Rubella Complications
Rubella is a mild infection. Once you've had the disease, you're usually permanently immune. About 70 percent of adult women with rubella experience arthritis in the fingers, wrists and knees, which generally lasts for about one month. In rare cases, rubella can cause an ear infection (otitis media) or
inflammation of the brain (encephalitis).
However, if you're pregnant when you contract rubella, the consequences for your unborn child may be severe. Up to 85 percent of infants born to mothers who had rubella during the first 11 weeks of pregnancy develop congenital rubella syndrome. This can cause one or more problems, including growth
retardation, cataracts, deafness, congenital heart defects and defects in other organs. The highest risk to the fetus is during the first trimester, but exposure later in pregnancy also is dangerous.
Fortunately, an average of fewer than 10 babies are born with congenital rubella syndrome in the United States each year. Rubella occurs most frequently in adults who never received vaccinations because they came from other countries where the MMR vaccine isn't widely used.
Rubella: Complications - MayoClinic.com