RESUMEN
Congenital toxoplasmosis is produced by intrauterine infection of the fetus with Toxoplasma gondii from a mother infected for the first time during her pregnancy and its clinical manifestations depend on the gestational age at the time of infection. This disease is considered a health problem in developed and underdeveloped countries and its early diagnosis is very important as part of the medical care to pregnant women. In this paper periodic screening of anti T. gondii antibodies was carried out in pregnant women from 8 health areas in two peripheral regions of the city Havana, Cuba during 1990 and 1991, by an indirect ELISA. In the first test performed before 12 weeks of pregnancy of was found that 70.9% of the women tested presented anti T. gondii antibodies. The remaining 1606 pregnant women (29.1%) were considered potentially susceptible, so the test was repeated during the second and third trimesters. Only 16(1%) of the negative patients showed antibody titers in the second or third test, confirming that they acquired the infection for the first time during pregnancy.