Prospective multicenter observational study to further develop and validate a preterm birth risk predictor, using a preterm cutoff at 37 0/7 weeks gestation and at 35 0/7 weeks gestation. A single maternal peripheral blood sample will be collected for analysis. Data related to potential risk factors for preterm birth will be obtained through maternal interview and review of medical records. Subjects will be followed through the delivery process to assess the course of pregnancy, labor, and to document any related maternal complications. Neonatal outcomes will be gathered from the medical record for up to 28 days of life or discharge, whichever occurs first.