Premature birth is one of the main causes of perinatal morbidity and mortality in developed and developing countries. Premature birth can be due to various factors, but infectious diseases are the main cause. Earlier, researchers from the Liverpool School of Tropical Medicine (Liverpool, UK) described an unusually high frequency of preterm births (20%) based on ultrasound data, as well as a high incidence of infections in a rural population of southern Malawi.

During the study, the effectiveness of using azithromycin over two gestational periods was studied to reduce the frequency of preterm births. The study involved 2,297 pregnant women randomized to receive azithromycin orally at a dose of 1 g administered once at 16-24 and 28-32 weeks of gestation.

Gestational age was determined by ultrasound for periods up to 24 weeks. Women and newborns were followed for a 6-week postnatal period. The primary outcome measure was the frequency of preterm births with a gestational age of less than 37 weeks. The secondary endpoints were mean gestational age at birth, perinatal mortality, weight of the newborn, malaria and maternal anemia. The analysis was performed for the entire population of women to be treated (ITT analysis).

There were no statistically significant differences in outcomes between the azithromycin group (n = 1,096) and the placebo group (n = 1,087) compared to (1) the preterm birth rate (16.8% and 17.4 %, respectively), the odds ratio (OR) 0.96, (95% confidence interval 0.76-1.21); (2) the average gestational age at the time of birth (38.5 and 38.4 weeks, respectively), the average difference is 0.16 (from -0.08 to 0.40); (3) the average weight of the newborn (3.03 and 2.99 kg, respectively), the average difference is 0.04 (from -0.005 to 0.08); (4) perinatal mortality (4.3% and 5.0%, respectively), OR 0.85 (95% CI 0.53-1.38); maternal malaria parasitaemia (11.5% and 10.1%, respectively), OS 1.11 (0.84-1.49) and maternal anemia (44.1% and 41.3%, respectively) from 28 - 32 weeks gestation, OR 1.07 (0.88-1.30).

A meta-analysis of the primary results from 7 other studies that examined routine antibiotic prophylaxis in pregnant women (more than 6,200 pregnant women) found no effect on routine prescribing of prophylactic antibiotics in pregnant women. rate of premature births (relative risk 1.02, 95% CI 0.86-1.22).

Thus, during this study, there was no evidence of the effectiveness of prophylactic use of antibiotics to prevent preterm delivery in high-risk pregnant women. According to the study authors, you should look for other methods of preventing premature births in women at risk of developing it.