Late second-trimester nonstress test characteristics in preterm delivery before 32 weeks of gestation.
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.
Yanagihara
T
T
Department of Perinatology, Kagawa Medical University, Miki, Japan. yanat@kms.ac.jp
Ueta
M
M
Hanaoka
U
U
Tanaka
Y
Y
Kuno
A
A
Kanenishi
K
K
Yamashiro
C
C
Tanaka
H
H
Hata
T
T
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