 Eight academic medical centers or sites had primary responsibility for enrollment and follow-up of study participants. Several of these sites collected data through additional academic research centers or nearby hospitals subsites. A Data Coordinating and Analysis Center DCAC provided input to the protocol, manages the data, and analyzes the data. Investigators from these institutions have established a partnership with NICHD staff to develop and implement the study protocol and ancillary studies that acquire and analyze data to identify biomarkers and understand the mechanism and prediction of preterm birth and other adverse pregnancy outcomes. 