The Genomic and Proteomic Network for Preterm Birth Research Case Control Study is a multi-center observational trial designed to determine if there is a genetic and/or proteomic predisposition to idiopathic preterm birth. Patients who deliver preterm (20-34 weeks’ gestation)will be the cases patients and the control patient consisting of patients who deliver between 39 and 41 weeks’ gestation. Maternal and infant DNA samples will be obtained for analysis and compared between the two groups. Data will be collected on the prenatal history and hospital course of the mother and infant. The total sample number is 1000, 500 in each group should be large enough to detect a difference.