When a woman contracts rubella during pregnancy, most of the time the baby is born with congenital rubella syndrome (CRS). The severity of CRS depends on what stage of pregnancy the woman is in when she catches the disease. Birth defects associated with CRS may include, deafness, heart problems, mental retardation, neurological abnormalities or vision defects; deafness is the most common CRS-related birth defect. Prematurity and other potential life-threatening conditions are also common in CRS. To prevent rubella during pregnancy, women of childbearing age should check their immunity statuses before getting pregnant.
Catching rubella during the first five months of pregnancy is extremely dangerous for the unborn baby. In approximately 80% of cases in which the woman contracts rubella during pregnancy, the fetus will become sick. The earlier that the unborn baby is exposed to rubella, the more severely she is likely to be affected.
If the mother catches rubella during the first 12 weeks of gestation, there is an 85% chance that the baby will be born with CRS, and during weeks 13-16, a 54% chance. Contracting rubella between the 17th and 20th weeks of pregnancy creates a high likelihood that the baby will be born deaf. After 20 weeks of gestation, most babies are born without CRS defects.
Babies born to mothers who contracted rubella during pregnancy may be premature and have a low birth weight. Liver infection, anemia, or a low blood platelet count might also affect the baby at birth. In addition, some babies with CRS have what medical professionals refer to as blueberry muffin lesions. These babies are born with jaundice and purple skin hemorrhages known as purpura. The rubella virus may also cause a miscarriage or stillbirth.
Once a woman contracts rubella during pregnancy, there is no way to know for sure if the baby will also be infected, or to what degree. All women of childbearing age may find out their rubella immunity statuses with a simple finger-stick blood test. If a woman finds that she is not immune to the rubella virus, she should be vaccinated right away and then wait a minimum of 28 days before trying to conceive. Although there have not been documented cases of CRS in pregnant women who get immunized, doctors recommend that women who are already pregnant wait until the baby is born before being immunized. Non-immune pregnant women can reduce their chances of catching rubella by avoiding people who have active rubella infections.