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

Objective

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.

Study Design

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.

Results

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).

Conclusion

The presence of abnormal FHR tracing patterns in meconium-stained amniotic fluid patients is associated with an increased risk of adverse perinatal outcomes.

Key words: fetal heart rate tracing, meconium-stained amniotic fluid