Prevention of toxoplasmosis during pregnancy--an epidemiologic survey over 22 consecutive years.

Abstract

Prevention of congenital toxoplasmosis is most often based on the results of a serological screening program in pregnant women followed by prenatal and postnatal treatment of women and their newborns when infection is already established during pregnancy or on cord blood (secondary prevention). Little effort has been made to study primary prevention of toxoplasmosis during pregnancy. To assess the possibilities of two different programs aimed at preventing the acquisition of toxoplasmosis during pregnancy. During the first study period (1979-1982) the natural incidence of toxoplasmosis in pregnancy was studied in 2986 pregnant women. In the second study period (1983-1990) the incidence of toxoplasmosis was studied in 8300 women. During this period, seronegative women received a written list of recommendations on how to avoid a toxoplasma infection during pregnancy. In the third study period (1991-2001) the incidence of toxoplasmosis was studied in 16,541 women. During this period, the prevention campaign consisted of a leaflet explaining a) toxoplasmosis as a disease and b) what measures should be taken to avoid toxoplasmosis during pregnancy. The third part of the campaign involved a reiteration of these recommendations during antenatal classes held around mid-gestation. The impact of the two prevention programs was studied by measuring the seroconversion rate in seronegative women. Twenty of 1403 seronegative women in the first period (1.43%), 19 of 3605 women in the second period (0.53%) and 8 of 8492 in the third period (0.09%) seroconverted during pregnancy. The first prevention campaign reduced the seroconversion rate by 63% (p<0.05 OR 2.729 95% CI 1.452-5.084). The second prevention program resulted in a reduction rate of 92% compared to the seroconversion rate in the first period (p<0.0001 OR 15.34 95% CI 6.741-34.89). Promotion of simple measures is very effective in the prevention of toxoplasmosis during pregnancy. Primary prevention should not only be based on education about preventive measures given by physicians, but these guidelines should be reiterated during antenatal classes and leaflets distributed containing written recommendations on the nature of the disease and its avoidance.