Rubella, also called German measles, is a contagious infection caused by a virus. It usually causes a mild illness with a fine, red rash over most of the body, swollen glands, and low fever.

Rubella is not common in the United States because most children are vaccinated (immunized) against it. Most people who get rubella are young adults who have not been vaccinated. A person can develop immunity to rubella by having the disease or being vaccinated.

Rubella is a mild illness in adults. However, if a woman gets rubella during her first 3 months of pregnancy, the unborn baby (fetus) has an increased risk for severe birth defects, such as heart defects, deafness, and cataracts. The illness can also result in miscarriage or stillbirth. The earlier the infection occurs in a woman's pregnancy, the greater the risk to her baby. Women who are not immune to rubella should be vaccinated before becoming pregnant.