The significance of fetal heart rate decelerations during nonstress testing.
Over a 9-month time span, eight gravid women at high risk had fetal heart rate decelerations on nonstress tests (NSTs). This form of antepartum evaluation, the standard at our institution, was performed 918 times on 476 women during this period. Decelerations were required to be between 1 and 10 minutes in duration and less than 90 bpm, or greater than 40 bpm below baseline, for inclusion. Of the eight women (1.7% of the total tested), four had reactive and four nonreactive NSTs. All eight had contraction stress tests (CSTs) that were negative by definition. Of four women allowed to labor, two (50%) required cesarean section for fetal distress. Two instances of fetal death (25%) occurred during observation periods of 36 and 48 hours. Two infants were growth retarded, and two had abnormal cord positions. NSTs showing decelerations of this type, regardless of reactivity or of follow-up CST, are abnormal and should be viewed with alarm. In term pregnancy, such fetuses should be delivered. In preterm pregnancy with nonreactive NSTs, decelerations may also be valid grounds for delivery. Some discrimination is possible in preterm pregnancies when the NST is reactive.
D005260:Female; D005316:Fetal Distress / Q000175:diagnosis* / Q000503:physiopathology; D005317:Fetal Growth Retardation / Q000175:diagnosis* / Q000503:physiopathology; D005318:Fetal Heart / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011248:Pregnancy Complications; D011379:Prognosis; D012306:Risk