Rubella - Infectious Diseases in Pregnancy

RUBELLA

Rubella (German, or 3-day, measles) is an RNA virus withimportant perinatal impact if infection occurs during pregnancy. Widespread immunization programs in the last 30 years have prevented periodic epidemics of rubella, but some women of reproductive age lack immunity to this virus and are therefore susceptible to infection. Once infec-tion occurs, immunity is life-long. A history of prior infec-tion is an unreliable indicator of immunity.

If a woman develops rubella infection in the first trimester of pregnancy, there is an increased risk of both spontaneous abortion and congenital rubella syndrome. Although most infants with congenital rubella appear nor-mal at birth, many subsequently develop signs of infection. Common defects associated with the syndrome include congenital heart disease (e.g., patent ductus arteriosus), mental retardation, deafness, and cataracts. The risk of congenital rubella is related to the gestational age at the time of infection; it is highest in the first month of preg-nancy and decreases with increasing gestational age. Pri-mary infection can be diagnosed by serologic testing for IgM and IgG antibodies during the acute and convales-cent stages of infection.

Because of the serious fetal implications, prenatal screening for IgG rubella antibody is routine. All pregnant women should be screened, unless they are known to be immune based on previ-ous serologic testing. Young women should be vaccinatedwhen they are not pregnant, if they are susceptible. The vaccine uses a live attenuated rubella virus that induces anti-bodies in virtually all women who have been vaccinated Because of this, pregnant women should not be vaccinated. It is recommended that pregnancy be delayed 1 month following immunization, although congenital rubella syn-drome following vaccination during an undiagnosed preg-nancy has not been reported. In women whose prenatal screen identifies a lack of rubella antibody, vaccination post-partum at the time of hospital discharge is recommended. Such management poses no risk to the newborn or other children; breastfeeding is not contraindicated.

If rubella is diagnosed in a pregnant woman, the patient should be advised of the risk of fetal infection and counseled regarding options for continuing the pregnancy.

Because there is no effective treatment for a pregnant patient infected with rubella, patients who do not have immunity are advised to avoid potential exposure.

Although immune globulin may be given to an infected woman, it does not prevent fetal infection. The absence of clinical signs in a woman who has received immune globu-lin does not guarantee that infection of the fetus has been prevented.