Prevention of Preterm Birth in 2014Overview of Spontaneous Preterm Birth A Complex and Multifactorial PhenotypeESPLIN, MICHAEL S. MD*,†Author Information *Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, University of Utah Health Sciences Center †Division of Maternal Fetal Medicine, Intermountain Healthcare, Salt Lake City, Utah M.S.E. serves on the scientific advisory board and holds stock in a private company called Sera Prognostics that was established to create a commercial test to predict preterm birth and other obstetric complications. Correspondence: Michael S. Esplin, MD, Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, University of Utah Health Sciences Center, Salt Lake City, UT. E-mail: [email protected] Clinical Obstetrics and Gynecology: September 2014 - Volume 57 - Issue 3 - p 518-530 doi: 10.1097/GRF.0000000000000037 Buy Metrics Abstract The phenotype of spontaneous preterm birth (SPTB) refers to the biochemical and physical characteristics present at the time of preterm delivery. These are the result of the processes that cause this complication. The lack of understanding about the etiologies and our inability to prevent SPTB are because of the complex nature and multiple processes responsible for maintenance of pregnancy and the transition to labor. Any of these processes, when activated prematurely, may lead to SPTB. This article provides an overview of the SPTB phenotype, which may assist with future attempts to reduce in the incidence of SPTB. © 2014 by Lippincott Williams & Wilkins.