Increased prevalence of malaria in HIV-infected pregnant women and its implications for malaria control

OBJECTIVES TO examine in pregnant women the relationship between HIV infect ion and malaria prevalence and to determine, in relation to HIV infection, the effectiveness of sulphadoxine-pyrimethamine in clearing P. falciparum i nfection. METHOD Descriptive cross-sectional analysis of P, falciparum prevalence in pregnant women at first antenatal visit and of women at delivery who had re ceived two sulphadoxine-pyrimethamine treatments fur malaria. HIV status wa s assessed in 621 women who attended for antenatal care and for delivery at two rural hospitals in southern Malawi in 1993-94. Information was collect ed on maternal age, parity and gestational age. Prevalence of P. falciparum was measured at first antenatal visit and delivery. Women were given two r outine treatment doses of sulphadoxine-pyrimethamine (SP), at first antenat al visit and between 28 and 34 weeks gestation, conforming to Malawi govern ment policy on antimalarial control during pregnancy. RESULTS Prevalence of HIV infection was 25.6% and all infections were HIV t ype-1. In primigravidae malaria prevalence at recruitment was 56.3% in HIV- infected and 36.5% in HIV-uninfected women (P = 0.04). The corresponding fi gures for multigravidae were 23.8% and 11.0%, respectively (P < 0.01). HIV- infected primigravidae had increased malaria prevalence at all gestational ages. Peak parasite prevalence occurred earlier in gestation in HIV-infecte d primigravidae (16-19 weeks if HIV-infected; 20-23 weeks if HIV-uninfected ). The relative risk for parasitaemia in HIV-infected compared to HIV-uninf ected women was significantly increased in three of five parity groups, inc luding dir two highest ones (parity >3), indicating parity-specific immunit y to malaria was impaired. Malaria prevalence at delivery remained high in HIV-infected women despite prior routine treatment with sulphadoxine-pyrime thamine in pregnancy There was no significant difference in parasite preval ence at delivery between women who did or did not use sulphadoxine-pyrimeth amine. CONCLUSIONS is HIV infection is associated with a significant increase in m alaria prevalence in pregnant women of all parities with the effect apparen t from early in gestation. Two treatment doses of sulphadoxine-pyrimethamin e were inadequate to clear parasitaemia in many women by the time of delive ry and this occurred independently of HIV status and despite high sensitivi ty to SP in this area. There is a need to undertake longitudinal studies to determine the incidence of P. falciparum infection in HIV-infected and uni nfected pregnant women and to reassess the frequency and timing of sulphado xine-pyrimethamine treatment doses in these women. Late pregnancy re-infect ions with P. falciparum probably explain the high parasite prevalence at de livery following sulphadoxine-pyrimethamins treatment at 28-34 weeks gestat ion.