Clinical associations of variable decelerations during reactive nonstress tests

Six hundred ninety-three patients at or beyond 30 weeks’ gestation with reactive nonstress tests (NSTs) were divided into groups based on the occurrence of variable decelerations of 15 seconds or more in duration and of 20 or more beats per minute in severity. Ultrasound examination within a month of testing showed no increases in nuchal cord localization or decreased amniotic fluid volumes in a subgroup of 181 patients. Fetuses with antepartum variable decelerations were more likely to demonstrate similar decelerations in labor (P <.001), to undergo operative delivery for a diagnosis of “distress ” (P <.05), to require intensive care nursery admission (P <.01), and to be small for gestational age (P <.01). No significant differences were noted in frequency of nuchal or other cord entanglements, overall cesarean section rate, or low pH or Apgar score values. We conclude that variable decelerations in the absence of other alarming NST findings may aid in identifying patients at risk for adverse perinatal occurrences, although factors other than nuchal cord placement or oligohydramnios may be responsible.