Treatment: A key drug in the fight against AIDS has previously unknown side effects that could shorten the life span of pregnant women who take it, new research shows.
Aid workers and governments across Africa have rolled out treatment of Nevirapine, a cheap, single-dose drug that dramatically reduces the chances of a HIV-positive mother passing the virus to her unborn child.
But fresh studies warn that Nevirapine can also increase the mother's resistance to treatment with antiretrovirals, the drugs that help prolong the lives of AIDS sufferers.
The finding, which was presented at the recent meeting of AIDS scientists in San Francisco, is a serious setback in the battle against disease that has infected 40 million people worldwide.
However, specialists said the unwanted side-effects should not discourage use of the drug.
Much of Southern Africa has been decimated by HIV. In some countries, one pregnant woman in five is infected, and they pass the virus to their babies about half the time.
Nevirapine is favoured by AIDS specialists because it is simple, cheap and effective. At a cost of about €3 per dose, it cuts the chances of mother-to-child transmission virus by up to 50 per cent.
The drug is one part of a double-pronged strategy promoted by the World Health Organisation (WHO) to halt the onslaught by using drugs. The other is treatment with anti-retrovirals to extend the lives of dying AIDS adults.
The WHO recently announced an ambitious plan to provide three million AIDS sufferers with anti-retrovirals by 2005, dubbed "3 by 5".
Some scientists have already begun discussing ways of administering Nevirapine differently - such as only to the baby - in order to circumvent its complications.
But the reality is that most pregnant women in developing countries cannot afford the anti-retroviral drugs anyway, said Ms Kate Carr of the Elizabeth Glaser Pediatric AIDS foundation, which has treated 50,000 pregnant women, mostly with Nevirapine.
"We know that combination therapy is better. That would be the ideal.
"But in most resource-poor settings, there is no other option," she told the Journal Sentinel newspaper.