Scientists have provided evidence that a single oral dose of azithromycin, a common antibiotic, reduced the risk of maternal sepsis or death by 33 per cent in women who delivered vaginally, according to a new study.

Maternal infection also increases the risk of neonatal sepsis, which accounts for 16 per cent of newborn deaths, the study said.

Maternal infections and sepsis, which is a serious complication of infections, are among the top five causes of maternal mortality worldwide, the study said.

Ten per cent of maternal deaths are caused by infections that occur shortly before, during or after delivery, the study said.

According to the study, the results from the Azithromycin Prevention in Labor Use Study, or A-PLUS, the trial led by investigators at the University of Alabama at Birmingham (UAB), US, enhanced information from previous UAB-led trials, which showed azithromycin administered before cesarean delivery reduced maternal infections.

The results are published in the New England Journal of Medicine.

The multi-country, randomised trial was conducted at eight sites in seven low- and middle-income countries in Africa, Asia and Latin America, the study said.

"The World Health Organisation and others have prioritised reducing maternal sepsis to reduce maternal deaths," said Alan Tita, professor in the UAB Department of Obstetrics and Gynaecology.

"Studies confirming the effectiveness of azithromycin for vaginal delivery, which is the most common mode of delivery, were lacking. We wanted to find a low-cost intervention that could be used globally to address this problem," said Tita.

From September 2020-August 2022, according to the study, more than 29,000 women were randomised to either an active or placebo group. Those in the active group were given a single 2-gram dose of azithromycin, the study said.

Maternal sepsis or death, the study's primary outcome, occurred in 1.6 per cent of women in the active group versus 2.4 per cent in the placebo group, the study said.

Additionally, rates of several secondary outcomes including specific maternal infections such as endometritis wound infections and urine infections were lower in the azithromycin group, the study said.

"In addition to the decrease in maternal infections, there were fewer maternal hospital readmissions and unscheduled visits for care in the first 42 days after delivery, which is consistent with findings from the large United States trial in women who underwent a cesarean birth," said Waldemar A. Carlo, co-lead of the A-PLUS trial.

While findings showed azithromycin reduced the risk of maternal sepsis or death, the intervention did not reduce the risk of sepsis or death in newborns, the study said. However, there were no adverse newborn effects, the study said.