Azithromycin not effective against peripartum infection in high-risk, labouring women

A single dose of oral azithromycin with or without amoxicillin falls short of reducing the risk of maternal peripartum or neonatal infection among women experiencing prolonged labour or rupture of membranes at term, a study has found.

The study screened 6,531 women with viable term nonanomalous pregnancies with either prolonged labour (≥18 hours) or rupture of membranes (≥8 hours). Those who had chorioamnionitis, study drug contraindications, or planned caesarean births were excluded.

A total of 756 women were randomized to treatment with oral azithromycin 1 g plus either placebo (group 1; n=253) or oral amoxicillin 2 g (group 2; n=253) or placebo plus another placebo (group 3; n=250). All women received usual care, including antibiotics given at the healthcare professional's discretion.

At baseline, patient characteristics such as body mass index, duration of rupture of membranes or labour, and parity were similar across the treatment groups, except for maternal age. Most of the women in each group received usual-care antibiotics; more than 90 percent received penicillin, and approximately 50 percent of antibiotic prescriptions were indicated for prolonged rupture of membranes across all treatment groups.

The primary outcome of a composite of maternal peripartum infection or death from any cause up to 6 weeks postpartum were similar between treatment groups (6 percent in group 1 and 7 percent in group 2 vs 10 percent in the placebo group 3; relative risk [RR], 0.6, 95 percent confidence interval [CI], 0.3–1.2 and RR, 0.7, 95 percent CI, 0.4–1.3, respectively).

Compared with group 3, group 2 had lower incidences of chorioamnionitis (3.2 percent vs 0.4 percent; p=0.02) and wound infection (4 percent vs 0.8 percent; p=0.02). There were no between-group differences seen in other maternal or neonatal outcomes, including neonatal infection.