Abnormal fetal heart rate tracing patterns in patients with thick meconium staining of the amniotic fluid: association with perinatal outcomes.

Abstract

The objective of the study was to evaluate, in labors complicated by thick meconium-stained amniotic fluid, the association between specific fetal heart rate (FHR) patterns and adverse perinatal outcomes. A retrospective cohort study of patients with FHR tracing data (n = 1638) from a previously reported randomized controlled trial of amnioinfusion for the prevention of meconium aspiration syndrome. The presence of FHR tracing abnormalities was associated with an increased risk of perinatal mortality and/or neonatal morbidity (moderately abnormal: adjusted odds ratio [OR], 1.67; 95% confidence interval [CI], 1.18-2.37; markedly abnormal: adjusted OR, 2.97; 95% CI, 1.88-4.67). Specific abnormalities that were associated with the risk of perinatal mortality and/or neonatal morbidity included prolonged decelerations (OR, 1.22; 95% CI, 1.02-1.48), severe variable decelerations (OR, 1.08; 95% CI, 1.00-1.16), bradycardia (OR, 2.49; 95% CI, 1.02-6.11), and tachycardia (OR, 2.43; 95% CI, 1.49-3.94). The presence of abnormal FHR tracing patterns in meconium-stained amniotic fluid patients is associated with an increased risk of adverse perinatal outcomes.