Prevalence of antibodies to Toxoplasma gondii in pregnant women in Oregon.

Sera from 95,929 pregnant women were screened for antibodies to Toxoplasma gondii with the indirect hemagglutination test (IHA) at a 1:64 dilution of the sera. An indirect fluorescent antibody-IgM specific test (IFA-IgM) was used on all sera found to have an IHA titer of greater than or equal to 1:256. From August 1973 to December 1976, 8.1% of pregnant women had IHA titers of greater than or equal to 1:64. In addition, 129 (18.4%) of 700 pregnant women with IHA titers of greater than or equal to 1:256 had IFA-IgM titers of greater than or equal to 1:4. The IHA test was an acceptable test for mass screening of sera from pregnant women. In Oregon, one in every 200 women contracts toxoplasmosis during her pregnancy.