The sera of 3,463 pregnant women were screened, at the first antenatal visit, for
antibodies to
rubella, cytomegalovirus (CMV) and Toxoplasma gondii.
Rubella antibodies were detected in 97.5%, CMV
antibodies in 71% and toxoplasma
antibodies in 45% of women. Asymptomatic
toxoplasmosis occurred during pregnancy in 3 of 609 (0.5%) and primary CMV
infection in 5 of 338 (1.5%) initially seronegative women whose sera were retested at the end of their pregnancies. The observed incidence of
toxoplasmosis was similar to that calculated on the basis of the age-related prevalence of
antibodies found in this study. On the basis of these observations it is estimated that
congenital toxoplasmosis and
congenital CMV infection due to primary maternal
infection each occurs in up to 2/1,000 infants in this community. Very few of these infants have obvious abnormalities at birth, but follow-up studies elsewhere have shown that many of them suffer significant long-term sequelae. Routine antenatal screening for
rubella antibodies is well established and justifiable for this preventable congenital
infection. However, routine antenatal screening for CMV
antibodies cannot be justified at present, since neither immunization nor treatment is available. Further information is required to determine the cost-effectiveness of routine antenatal screening for toxoplasma
antibodies and treatment of proven maternal
infection during pregnancy.