Can malaria chemoprophylaxis be restricted to first pregnancies?

The harmful effects of malaria are most pronounced during first pregnancies and chemoprophylaxis is most effective when given at this time. However, restriction of chemoprophylaxis to first pregnancies might lead to enhanced susceptibility to malaria during second pregnancies. We have investigated this possibility by studying the outcome of second pregnancies in 165 Gambian women who had received either malaria chemoprophylaxis with Maloprim or placebo during their first pregnancy. Many of these primigravidae did not present until the third trimester of pregnancy so that some are likely to have experienced a malaria infection before they started medication. The prevalence of malaria infection of the blood and of the placenta during second pregnancies was similar in women who had received chemoprophylaxis during their first pregnancy and in those who had not, and the mean birth weights of babies born to women in each group were almost identical. Thus, in areas where the epidemiology of malaria is similar to that of The Gambia and where most women present relatively late in pregnancy, it may be possible to restrict malaria chemoprophylaxis to first pregnancies with consequent savings in cost and a reduction in drug pressure on Plasmodium falciparum.