The COVID-19 Resource Centre, established by Elsevier in January 2020, provides free information in English and Mandarin on the novel coronavirus. Elsevier grants permission to make all its COVID-19-related research available in PubMed Central and other public repositories, allowing unrestricted reuse and analysis with proper attribution as long as the resource centre remains active. The paper discusses preterm birth, a leading cause of perinatal morbidity and mortality in developed countries. Preterm births occur before 37 weeks of gestation and are categorized into three types: spontaneous labour with intact membranes, preterm premature rupture of membranes (PPROM), and labour induction or caesarean delivery for maternal or fetal indications. The frequency of preterm births varies by location, ranging from 5-9% in many developed countries to 12-13% in the USA. The rate has increased in many areas due to rising indicated preterm births and preterm deliveries of artificially conceived multiple pregnancies. Spontaneous preterm births are associated with multiple risk factors, including previous preterm birth, black race, periodontal disease, and low maternal body mass index. Short cervical length and elevated cervical-vaginal fetal fibronectin concentration are strong predictors of spontaneous preterm birth. Indicated preterm births are often due to conditions like pre-eclampsia or intrauterine growth restriction. PPROM is defined as membrane rupture before 37 weeks, often due to asymptomatic intrauterine infection. The paper explores the epidemiology, causes, and mechanisms of preterm births, highlighting the role of infection, inflammation, uteroplacental ischemia, uterine overdistension, stress, and other immunologically mediated processes. Maternal risk factors include demographic characteristics, nutritional status, pregnancy history, and psychological and social stress. Intrauterine infection is a significant contributor, with bacterial vaginosis being particularly common and associated with increased risk. The paper also discusses the potential genetic components of preterm birth and the importance of biomarkers for prediction and prevention.The COVID-19 Resource Centre, established by Elsevier in January 2020, provides free information in English and Mandarin on the novel coronavirus. Elsevier grants permission to make all its COVID-19-related research available in PubMed Central and other public repositories, allowing unrestricted reuse and analysis with proper attribution as long as the resource centre remains active. The paper discusses preterm birth, a leading cause of perinatal morbidity and mortality in developed countries. Preterm births occur before 37 weeks of gestation and are categorized into three types: spontaneous labour with intact membranes, preterm premature rupture of membranes (PPROM), and labour induction or caesarean delivery for maternal or fetal indications. The frequency of preterm births varies by location, ranging from 5-9% in many developed countries to 12-13% in the USA. The rate has increased in many areas due to rising indicated preterm births and preterm deliveries of artificially conceived multiple pregnancies. Spontaneous preterm births are associated with multiple risk factors, including previous preterm birth, black race, periodontal disease, and low maternal body mass index. Short cervical length and elevated cervical-vaginal fetal fibronectin concentration are strong predictors of spontaneous preterm birth. Indicated preterm births are often due to conditions like pre-eclampsia or intrauterine growth restriction. PPROM is defined as membrane rupture before 37 weeks, often due to asymptomatic intrauterine infection. The paper explores the epidemiology, causes, and mechanisms of preterm births, highlighting the role of infection, inflammation, uteroplacental ischemia, uterine overdistension, stress, and other immunologically mediated processes. Maternal risk factors include demographic characteristics, nutritional status, pregnancy history, and psychological and social stress. Intrauterine infection is a significant contributor, with bacterial vaginosis being particularly common and associated with increased risk. The paper also discusses the potential genetic components of preterm birth and the importance of biomarkers for prediction and prevention.