7 - Maternal and foetal infection

Summary

In recent years, significant progress has been made in the early diagnosis of toxoplasma infection in the mother, the foetus and the newborn. The management of women infected during pregnancy has been greatly improved by the ability to diagnose the infection prenatally; also, the treatment of congenital infection is now initiated before birth. However, the prevention of infection in pregnant women should be reinforced with education about hygiene; in addition, advances in the prevention of late sequellae in infected offsprings should be made by using optimal treatments that have yet to be evaluated.

Maternal infection

Every instance of primary maternal toxoplasmosis occuring during pregnancy exposes the foetus to the risk of infection via the transplacental route, whereas the foetus is protected when maternal infection is prior to pregnancy. However, rare cases of congenital infection as the result of a maternal infection primarily acquired before pregnancy have been reported, either in immunocompromised women or in women infected shortly before conception.

Incidence

The rate of primary infection in pregnant women can be estimated by a serological follow-up of those who are susceptible (seronegative) at the beginning of pregnancy, or by age-specific seroprevalence surveys (Papoz et al. 1986; Ades & Nokes 1993). The prevalence of specific IgG antibodies indicating past exposure to toxoplasma may vary according to the sensitivity of the serological method used, but mainly depends on the epidemiological conditions pertaining to each geographical area.