Preterm delivery (PTD) is a leading cause of neonatal mortality and continues to be a major public health concern, reaching 12.9% in 2006, despite intense research to reverse this trend. Currently, fetal fibronectin (fFN) screening and cervical length determined by ultrasound are two tests which are proven to have benefit in the identification of those at greatest risk for preterm delivery. However the benefit of these tests is limited to situations where a negative result can avoid unnecessary interventions. The first goal of this study is to identify non-invasive predictor(s) that will increase the clinician's ability to identify patients who present with second trimester preterm labor (PTL) at risk for preterm delivery (PTD) ≤ 32 weeks gestation.