Introduction: Guadeloupe has a high rate of preterm birth despite access to healthcare comparable to that in mainland France. The launch of a prospective study (the Timoun cohort) in Guadeloupe offers an opportunity to better understand the risk factors for preterm birth in a population of African descent. The objective of this study was to assess the risk factors for preterm birth in this cohort. Population and methods: The Timoun mother-child cohort includes 1,068 women who attended prenatal clinics in Guadeloupe’s maternity wards between 2004 and 2007. Sociodemographic and medical data, as well as information on dietary habits during pregnancy, were collected via questionnaire and from medical records. Chlordecone concentrations were measured in maternal blood samples collected at delivery. Results: In the cohort, 144 preterm births (15.8%) occurred. The main risk factors identified were pregnancy-related conditions (pregnancy-induced hypertension, gestational diabetes, urinary tract infections, asthma, lupus), advanced maternal age, and living without a partner. Chronic exposure to chlordecone is associated with a shorter gestational duration. Finally, a Mediterranean-style diet during pregnancy is associated with a reduced risk of preterm birth specifically among overweight or obese women. Discussion and Conclusion: Our findings confirm the particular vulnerability of this population to the risk of preterm birth, due to the high prevalence of pregnancy-related conditions, certain social factors, and environmental pollution from chlordecone.