Thoughts on malaria in pregnancy with consideration of some factors which influence remedial strategies.

There is evidence that pregnancy enhances the clinical severity of malaria, especially of P. falciparum infections. In pregnant women with little or no prior experience of the disease, P. falciparum causes severe clinical illness, substantial malaria mortality, increased rates of abortion and stillbirth and low birthweight of offspring; moreover, in such women, the clinical consequences seen unmodified by maternal parity. However, in pregnant women resident in highly endemic areas who have acquired considerable immunity through prolonged prior contact with malaria, parity appears to influence susceptibility to an important degree. Women who are pregnant for the first time are most affected, showing increased prevalence and density of parasitaemia, increased frequency of clinical illness (but not mortality) and significantly increased frequency of delivery of low birthweight children. In contrast, in multigravid women these clinical features are much less obvious and rarely attain statistical significance. The differences in susceptibility to malaria of pregnant women associated with parity and previous immunological experience require that protective strategies must be planned with full knowledge of the local epidemiology of malaria and be specifically targeted to the women who require them. Furthermore, the effectiveness of each strategy requires careful monitoring to permit such modifications as may be required by change in the immune status of the resident population.