title: Late second-trimester nonstress test characteristics in preterm delivery before 32 weeks of gestation.
abstract: OBJECTIVE
  To clarify electronic fetal heart rate (FHR) monitoring characteristics in pregnancies with preterm delivery before 32 weeks of gestation, using the late second-trimester nonstress test.
  
  
  METHODS
  Among 953 children born from 1993 to 1996, we identified 100 singleton infants born before 32 weeks of gestation in whom second-trimester (24-27 weeks of gestation) electronic fetal monitoring (EFM) records were obtained. Individual components of the FHR patterns [baseline rate, baseline FHR variability, presence of acceleration (at least 10 beats/min for at least 10 s) and periodic or episodic deceleration (at least 25 beats/min for at least 15 s)] and birth characteristics were compared between pregnancy with or without second-trimester decelerations.
  
  
  RESULTS
  Among 100 infants, 65 had and 35 did not have second-trimester decelerations. There were no significant differences in gestational age at birth, birth weight, cord arterial blood pH, Apgar score and meconium staining between pregnancies with second-trimester decelerations and those without second-trimester decelerations. There were no significant differences in baseline rate and baseline variability between pregnancies with or without second-trimester decelerations. The number of accelerations in pregnancies with second-trimester decelerations was significantly more frequent than that in pregnancies without second-trimester decelerations (p < 0.001). There was a significant increase in the occurrence of premature rupture of the membranes (PROM; 60.0%) in pregnancies with second-trimester decelerations, when compared with events (37.1%) related to pregnancies without second-trimester decelerations (p < 0.05). There were no significant differences in the onset of breech presentation, cervical incompetency, preeclampsia and abnormal FHR pattern at birth between pregnancies with second-trimester decelerations and those without second-trimester decelerations. Pregnancies with PROM after second-trimester EFM were significantly more likely to have second-trimester decelerations than those without PROM (75.0 vs. 54.2%, p < 0.05).
  
  
  CONCLUSIONS
  Periodic or episodic decelerations during late second-trimester EFM were associated with an increased risk of the occurrence of PROM in pregnancies with preterm delivery before 32 weeks of gestation.
authors.affiliation: Department of Perinatology, Kagawa Medical University, Miki, Japan. yanat@kms.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Yanagihara
authors.forename: M
authors.initials: M
authors.lastname: Ueta
authors.forename: U
authors.initials: U
authors.lastname: Hanaoka
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
authors.forename: A
authors.initials: A
authors.lastname: Kuno
authors.forename: K
authors.initials: K
authors.lastname: Kanenishi
authors.forename: C
authors.initials: C
authors.lastname: Yamashiro
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Hata
mesh_terms: D000328:Adult; D001034:Apgar Score; D001724:Birth Weight; D001946:Breech Presentation; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005322:Premature Rupture of Fetal Membranes / Q000503:physiopathology; D005323:Fetal Monitoring; D005865:Gestational Age; D006340:Heart Rate, Fetal; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D007234:Infant, Premature; D008470:Meconium; D007752:Obstetric Labor, Premature / Q000503:physiopathology*; D011225:Pre-Eclampsia / Q000503:physiopathology; D011247:Pregnancy; D002581:Uterine Cervical Incompetence / Q000503:physiopathology