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.