SciDev.Net

Research suggests that a commonly used antimalarial drug still prevents the adverse effects of malaria in pregnant women, but that women with HIV need more frequent doses.

The study is published today (June 20) in the Journal of the American Medical Association (JAMA).

Feiko ter Kuile, from the UK-based Liverpool School of Tropical Medicine, and colleagues sought to find out whether increasing the frequency of doses of the drug sulfadoxine-pyrimethamine — the only preventative antimalarial drug currently used during pregnancy — would reduce the adverse effects of malaria during pregnancy.

Women are especially vulnerable to the adverse effects of malaria — such as placental malaria, anaemia and low birth weight of their baby — during their first and second pregnancies, according to the World Health Organization (WHO).

Countries with sulfadoxine-pyrimethamine resistance urgently need information on whether the drug is still effective for women during pregnancy, the authors write.

The researchers reviewed several African studies on the efficacy of intermittent preventive therapy — a strategy where doses of the drug are given at pre-specified times, regardless of the presence of the malaria parasite or symptoms of illness.

They found that two doses of sulfadoxine-pyrimethamine during first or second pregnancies reduced the risk of placental malaria by 52 per cent, low birth weight by 29 per cent and anaemia by ten per cent.

But they found that pregnant women with HIV needed more frequent doses to prevent adverse effects. Those who were given monthly doses experienced less placental malaria and their babies had a higher birth weight.

For pregnant women who didn't have HIV, there was no clear benefit from receiving more frequent doses.

According to the WHO, HIV weakens pregnant women's immunity to malaria and also weakens malaria treatment.

Willis Akhwale, head of malaria control at Kenya's Ministry of Health, says Kenya has already recommended giving extra doses of the drug to HIV-positive women, especially in areas of high HIV/AIDS prevalence.

The authors warn that although the review shows that pregnant women still respond well to sulfadoxine-pyrimethamine, drug resistance is likely to develop, and there is an urgent need to explore alternative drugs.

Andrew Githeko, of the Kenya Medical Research Institute, says resistance to sulfadoxine-pyrimethamine is already high, and there should be further clinical trials on the effect of artemisinin-based drugs in pregnant women.

"Coartem [an artemisinin-based combination treatment] which is recommended for malaria treatment in Kenya is effective, but is yet to be cleared for use in pregnant women. Once such studies confirm its efficacy, despite being expensive, it will mark a major breakthrough," Githeko told SciDev.Net.

Link to full paper in the Journal of the American Medical Association 

Reference: Journal of the American Medical Association 297, 2603 (2007)