Better drugs needed for pregnant women in tropics

HONG KONG (Reuters) - More studies are urgently needed to find new and improved drugs to treat tropical diseases in pregnant women, scientists in Thailand said.

In an article published in PLoS Medicine, they said that while governments in developed countries had begun encouraging pharmaceutical companies to find new drugs for pregnant women, this was visibly absent in the tropics.

"There are few or no studies in pregnancy on most drugs used for the treatment of tropical infections, and so, few or no evidence-based recommendations," Nicholas White and his colleagues at Mahidol University's Mahidol-Oxford Tropical Medicine Research Unit wrote. (The article can be found ">here

doi=10.1371/journal.pmed.0050133) As such, pregnant women in these regions who are infected with potentially fatal illnesses may be treated with inferior drugs to avoid a hypothetical risk to the unborn child.

Out of an estimated 536,000 maternal deaths in the world in 2005, 533,000 or 99 percent occurred in developing countries in the tropics, they added.

The scientists, who are all malaria experts, said better drugs were needed in particular to treat malaria in pregnancy, which threatens the life of both mother and child.

Malaria in pregnancy reduces birth weight, and thereby, infant survival. Even when the mother is asymptomatic, the presence of malaria parasites in the blood is always harmful to the fetus and must be treated promptly and effectively, they said.

The scientists used the example of artesunate, a compound extracted from the Sweet Wormwood shrub and which is regarded by medical experts as the best treatment for malaria.

Although it has been shown to reduce the death rate of severe malaria by 35 percent compared with quinine, the latter is still the most widely used treatment for severe malaria in pregnancy.

"Somehow, the unknown, but certainly very small, risk to the fetus posed by artesunate is considered to exceed the 35 percent increased risk of both mother and baby dying from malaria," they wrote.

They called on international agencies and investors to support studies to find treatment for tropical diseases in pregnancy.

"We do not know how best to treat most tropical infectious diseases in pregnancy. It is a difficult problem, but one that should no longer be ignored," they wrote.

(Reporting by Tan Ee Lyn; Editing by Roger Crabb)