A drug given to pregnant women to combat malaria also offers protection against sexually transmitted infections (STIs), and boosting doses of the "double protection" treatment cuts the risk of infant deaths, researchers said on Thursday.

Giving pregnant women regular doses of antimalarial drugs greatly reduces the danger of life-threatening birth problems linked to the mosquito-borne disease and STIs, a study led by the London School of Hygiene & Tropical Medicine (LSHTM) said.

Many of the 880,000 stillbirths and 1.2 million newborn deaths which occur each year in sub-Saharan Africa are linked to the mother having an infection, the study found.