The benefits of a landmark treatment for HIV outweigh the risks, despite the fact it has been linked to birth defects in babies born to mothers taking the drug, researchers have said.

The antiretroviral drug dolutegravir, taken in conjunction with other drugs to suppress an HIV patient’s viral load and to stop them passing the virus to others, is considered one of the best HIV drugs available and has become the cornerstone of treatment in many richer countries since it was first introduced in the United States in 2013.

A cheaper generic version of the drug is also available, paving the way for its widespread adoption in poorer countries.

However, a study last year in Botswana found that the new drug was linked to an increase in neural tube defects – problems with the spine and skull that can happen in early pregnancy. The study found that babies born to women taking the drug at the time of conception were seven times more likely to have the defect than mothers who did not take the drug.

This prompted the World Health Organization to issue an alert on the safety of the dolutegravir, advising women of childbearing age to use other treatments.