(See also Other Viruses: Rubella.)
Congenital rubella is a viral infection acquired from the mother during pregnancy. Signs are multiple congenital anomalies that can result in fetal death. Diagnosis is by serology and viral culture. There is no specific treatment. Prevention is by routine vaccination.
Congenital rubella typically results from a primary maternal infection. Congenital rubella is rare in the US.
Rubella is believed to invade the upper respiratory tract, with subsequent viremia and dissemination of virus to different sites, including the placenta. The fetus is at highest risk of developmental abnormalities when infected during the first 16 wk of gestation, particularly the first 8 to 10 wk. Early in gestation, the virus is thought to establish a chronic intrauterine infection. Its effects include endothelial damage to blood vessels, direct cytolysis of cells, and disruption of cellular mitosis.
Symptoms and Signs
Rubella in a pregnant woman may be asymptomatic or characterized by upper respiratory tract symptoms, fever, lymphadenopathy (especially in the suboccipital and posterior auricular areas), and a maculopapular rash. This illness may be followed by joint symptoms.
In the fetus there may be no effects, multiple anomalies, or death in utero. The most frequent abnormalities include intrauterine growth restriction, microcephaly, meningoencephalitis, cataracts, retinopathy, hearing loss, cardiac defects (patent ductus arteriosus and pulmonary artery stenosis), hepatosplenomegaly, and bone radiolucencies. Others are thrombocytopenia with purpura, dermal erythropoiesis resulting in bluish red skin lesions, adenopathy, hemolytic anemia, and interstitial pneumonia. Close observation is needed to detect subsequent hearing loss, intellectual disability, abnormal behavior, endocrinopathies (eg, diabetes mellitus), or a rare progressive encephalitis. Infants with congenital rubella infections may develop immune deficiencies such as hypogammaglobulinemia.
Pregnant women routinely have a serum rubella titer measured early in pregnancy. Titer is repeated in seronegative women who develop symptoms or signs of rubella; diagnosis is made by seroconversion or a ≥ 4-fold rise between acute and convalescent titers. Virus may be cultured from nasopharyngeal swabs but grows very slowly, making swabs an inefficient method of diagnosis.
Infants suspected of having congenital rubella should have antibody titers and viral cultures. Persistence of rubella-specific IgG in the infant after 6 to 12 mo suggests congenital infection. Increased rubella-specific IgM antibodies also indicate rubella. Specimens from the nasopharynx, urine, CSF, buffy coat, and conjunctiva may grow virus; samples from the nasopharynx usually offer the best sensitivity, and the laboratory should be notified that rubella virus is suspected. In a few centers, diagnoses can be made prenatally by isolating the virus from amniotic fluid, detecting rubella-specific IgM in fetal blood, or applying reverse transcriptase–PCR (RT-PCR) techniques to fetal blood or chorionic villus biopsy specimens.
Other tests include a CBC with differential, CSF analysis, and x-ray examination of the bones to detect characteristic radiolucencies. Thorough ophthalmologic and cardiac evaluations are also useful.
No specific therapy is available for maternal or congenital rubella infection. Women exposed to rubella early in pregnancy should be informed of the potential risks to the fetus. Some experts recommend giving nonspecific immune globulin (0.55 mL/kg IM) for exposure early in pregnancy, but this treatment does not guarantee prevention, and the use of immune globulin should be considered only in women who decline termination.
Rubella can easily be prevented by vaccination. In the US, infants should receive vaccination for rubella together with measles and mumps vaccinations at 12 to 15 mo of age and again at entry to grade school or junior high school (see Table 13: Approach to the Care of Normal Infants and Children: Recommended Immunization Schedule for Ages 7–18 yr). Postpubertal females who are not known to be immune to rubella should be vaccinated. (Caution: Rubella vaccination is contraindicated in immunodeficient or pregnant women.) After vaccination, women should be advised not to become pregnant for 28 days. Efforts should also be made to screen and vaccinate high-risk groups, such as hospital and child care workers, military recruits, recent immigrants, and college students. Women who are found to be susceptible during prenatal screening should be vaccinated after delivery and before hospital discharge.
Last full review/revision October 2009 by Mary T. Caserta, MD