Decline of placental malaria in southern Ghana after the implementation of intermittent preventive treatment in pregnancy.

BACKGROUND: Intermittent preventive treatment in pregnancy with sulphadoxine-pyrimethamine (IPTp-SP) has been adopted as policy by many countries in sub-Saharan Africa. However, data on the post-implementation effectiveness of this measure are scarce. METHODS: Clinical and parasitological parameters were assessed among women delivering at a district hospital in rural southern Ghana in the year 2000 when pyrimethamine chemoprophylaxis was recommended (n = 839) and in 2006 (n = 226), approximately one year after the implementation of IPTp-SP. Examinations were performed in an identical manner in 2000 and 2006 including the detection of placental Plasmodium falciparum infection by microscopy, histidine-rich protein 2, and PCR. RESULTS: In 2006, 77% of the women reported to have taken IPTp-SP at least once (26%, twice; 24%, thrice). In 2006 as compared to 2000, placental P. falciparum infection was reduced by 43-57% (P < 0.0001) and maternal anaemia by 33% (P = 0.0009), and median birth weight was 130 g higher (P = 0.02). In 2006, likewise, women who had taken > or = 1 dose of IPTp-SP revealed less infection and anaemia and their children tended to have higher birth weights as compared to women who had not used IPTp-SP. However, placental P. falciparum infection was still observed in 11% (microscopy) to 26% (PCR) of those women who had taken three doses of IPTp-SP. CONCLUSION: In southern Ghana, placental malaria and maternal anaemia have declined substantially and birth weight has increased after the implementation of IPTp-SP. Likely, these effects can further be increased by improving IPTp-SP coverage and adherence. However, the remnant prevalence of infection in women having taken three doses of IPTp-SP suggests that additional antimalarial measures are needed to prevent malaria in pregnancy in this region.

Detection and clinical manifestation of placental malaria in southern Ghana.

BACKGROUND: Plasmodium falciparum can be detected by microscopy, histidine-rich-protein-2 (HRP2) capture test or PCR but the respective clinical relevance of the thereby diagnosed infections in pregnant women is not well established. METHODS: In a cross-sectional, year-round study among 839 delivering women in Agogo, Ghana, P. falciparum was screened for in both, peripheral and placental blood samples, and associations with maternal anaemia, low birth weight (LBW) and preterm delivery (PD) were analysed. RESULTS: In peripheral blood, P. falciparum was observed in 19%, 34%, and 53% by microscopy, HRP2 test, and PCR, respectively. For placental samples, these figures were 35%, 41%, and 59%. Irrespective of diagnostic tool, P. falciparum infection increased the risk of anaemia. Positive peripheral blood results of microscopy and PCR were not associated with LBW or PD. In contrast, the HRP2 test performed well in identifying women at increased risk of poor pregnancy outcome, particularly in case of a negative peripheral blood film. Adjusting for age, parity, and antenatal visits, placental HRP2 was the only marker of infection associated with LBW (adjusted odds ratio (aOR), 1.5 (95%CI, 1.0-2.2)) and, at borderline statistical significance, PD (aOR, 1.4 (1.0-2.1)) in addition to anaemia (aOR, 2.3 (1.7-3.2)). Likewise, HRP2 in peripheral blood of seemingly aparasitaemic women was associated with PD (aOR, 1.7 (1.0-2.7)) and anaemia (aOR, 2.1 (1.4-3.2)). CONCLUSION: Peripheral blood film microscopy not only underestimates placental malaria. In this highly endemic setting, it also fails to identify malaria as a cause of foetal impairment. Sub-microscopic infections detected by a HRP2 test in seemingly aparasitaemic women increase the risks of anaemia and PD. These findings indicate that the burden of malaria in pregnancy may be even larger than thought and accentuate the need for effective anti-malarial interventions in pregnancy.