This trial will assess whether a single dose of azithromycin (or placebo) given shortly before birth will reduce maternal and infant infections requiring antibiotic intervention in the 6 weeks following the birth, Pregnant women will be randomised close to time of delivery, and followed up for 6 weeks. Nasopharyngeal and vaginal swabs will be collected to monitor the impact of azithromycin on colonisation and resistance. Primary outcome assessment of new infections will be done by review of clinical presentations at primary health care and hospital.