Every year, 13 million babies are born too soon. Preterm babies have a higher risk of dying or developing less well. Preterm birth is particularly common in Africa, where HIV infection during pregnancy increases the risk of preterm birth. Infection and inflammation may cause preterm birth by weakening the membranes and triggering the start of labour. We believe pregnant women with HIV have more infections and inflammation which increases their preterm risk. Our project aims to understand why babies are born preterm in Zimbabwe and whether an inexpensive antibiotic can reduce infections and inflammation. Overall, we hope to understand how bacteria and immune responses aect the risk of preterm birth in Africa, and explore whether antibiotics reduce preterm birth. We will work in partnership with the Zimbabwean Ministry of Health and Child Care to disseminate our findings to people in the rural community where the trial was done, and to policymakers who write guidelines about how to prevent preterm births.