Pregnancy disorders that lead to delivery before the 28th week of gestation: an epidemiologic approach to classification

UMMS Affiliation

Department of Obstetrics and Gynecology

Publication Date


Document Type



Adult; Female; Humans; Infant, Low Birth Weight; Infant, Newborn; Obstetric Labor, Premature; Pregnancy; Pregnancy Complications; Smoking; United States


Obstetrics and Gynecology


Epidemiologists have grouped the multiple disorders that lead to preterm delivery before the 28th week of gestation in a variety of ways. The authors sought to identify characteristics that would help guide how to classify disorders that lead to such preterm delivery. They enrolled 1,006 women who delivered a liveborn singleton infant of less than 28 weeks' gestation at 14 centers in the United States between 2002 and 2004. Each delivery was classified by presentation: preterm labor (40%), prelabor premature rupture of membranes (23%), preeclampsia (18%), placental abruption (11%), cervical incompetence (5%), and fetal indication/intrauterine growth restriction (3%). Using factor analysis (eigenvalue = 1.73) to compare characteristics identified by standardized interview, chart review, placental histology, and placental microbiology among the presentation groups, the authors found 2 broad patterns. One pattern, characterized by histologic chorioamnionitis and placental microbe recovery, was associated with preterm labor, prelabor premature rupture of membranes, placental abruption, and cervical insufficiency. The other, characterized by a paucity of organisms and inflammation but the presence of histologic features of dysfunctional placentation, was associated with preeclampsia and fetal indication/intrauterine growth restriction. Disorders leading to preterm delivery may be separated into two groups: those associated with intrauterine inflammation and those associated with aberrations of placentation.

DOI of Published Version



Am J Epidemiol. 2008 Nov 1;168(9):980-9. Epub 2008 Aug 27. Link to article on publisher's site

Journal/Book/Conference Title

American journal of epidemiology

Related Resources

Link to Article in PubMed

PubMed ID