This document defines terms related to preterm birth such as gestational age, birth weight, and viability thresholds. It discusses the morbidity of preterm birth and contributing factors such as prior preterm birth, infection, lifestyle factors, and cervical changes. Diagnosis involves assessing cervical length, funneling, and fetal fibronectin levels. Management of preterm rupture of membranes and preterm labor is also outlined, including expectant management, risks, and use of tocolytics and antimicrobial therapy.