title: Length of latency with preterm premature rupture of membranes before 32 weeks' gestation.
abstract: OBJECTIVE
  The objective of the article is to describe latency for patients with preterm premature membrane rupture (PPROM) between 24(0/7) and 31(6/7) weeks' gestation.
  
  
  METHODS
  Secondary analysis of data collected prospectively in a multicenter clinical trial of magnesium sulfate for cerebral palsy prevention. Women with PPROM and fewer than six contractions per hour at enrollment who were candidates for expectant management (n = 1,377) were included in this analysis. Length of latency was calculated in days by subtracting the time of delivery from the time of membrane rupture.
  
  
  RESULTS
  At each week of gestation, median latency between 24 and 28 weeks was similar at approximately 9 days, but it was significantly shorter with PPROM at 29, 30, and 31 weeks (p < 0.001). In addition, the percentage of patients remaining undelivered at 7 days and 14 days was similar for PPROM between 24 and 28 weeks, but it decreased significantly after that. For each gestational age, the proportion of patients remaining pregnant declined in a fashion similar to an exponential pattern.
  
  
  CONCLUSIONS
  Median latency after PPROM is similar from 24 to 28 weeks' gestation, but it shortens with PPROM at and after 29 weeks.
authors.affiliation: Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Peaceman
authors.affiliation: Department of Obstetrics and Gynecology, The George Washington University Biostatistics Center, Washington, District of Columbia.
authors.forename: Yinglei
authors.initials: Y
authors.lastname: Lai
authors.affiliation: Department of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham Alabama.
authors.forename: Dwight J
authors.initials: DJ
authors.lastname: Rouse
authors.forename: Catherine Y
authors.initials: CY
authors.lastname: Spong
authors.affiliation: Department of Obstetrics and Gynecology, Case Western Reserve University-MetroHealth Medical Center, Cleveland, Ohio.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Mercer
authors.affiliation: Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, Utah.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Varner
authors.affiliation: Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: John M
authors.initials: JM
authors.lastname: Thorp
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Health Science Center at Houston, Houston, Texas.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Ramin
authors.affiliation: Department of Obstetrics and Gynecology, Columbia University, New York, New York.
authors.forename: Fergal D
authors.initials: FD
authors.lastname: Malone
authors.affiliation: Department of Obstetrics and Gynecology, University of Miami, Miami, Florida.
authors.forename: Mary J
authors.initials: MJ
authors.lastname: O'Sullivan
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas.
authors.forename: Gary D V
authors.initials: GD
authors.lastname: Hankins
mesh_terms: D000328:Adult; D015331:Cohort Studies; D036861:Delivery, Obstetric; D005260:Female; D005322:Premature Rupture of Fetal Membranes; D006801:Humans; D016015:Logistic Models; D015999:Multivariate Analysis; D010298:Parity; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D059285:Pregnancy, Twin / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012907:Smoking / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult