Objectives: To determine labour management procedures associated with an increased risk of fetal heart rate anomalies and to assess the effectiveness of various intrauterine resuscitation techniques for fetal distress.
Methods: The literature search was carried out systematically on Medline and Cochrane database between 1980 and June 2007 was performed.
Results: Early amniotomy and/or active management of labour reduce the duration of the first stage of labour without affecting the rate of caesarean section (level of evidence 1). Early amniotomy increases the frequency of severe variable fetal heart rate decelerations (level of evidence 1). High doses of oxytocin and decrease in the oxytocin-dosing interval for augmentation of labour both induce uterine hyperstimulation (level of evidence 1). Increased uterine activity is associated with a higher incidence of fetal heart rate abnormalities and neonatal acidosis (level of evidence 3). Fetal heart rate decelerations in supine position may disappear in the lateral position (level of evidence 3). In prophylactic maternal oxygenation administration abnormal cord blood pH values (less than 7.2) are more frequent in the oxygenation group than in the control group (level of evidence 2) and its efficacy in fetal distress is not evaluated until now. Amnioinfusion in the presence of thick meconium staining does not reduce the risk of perinatal death or meconium aspiration syndrome (level of evidence 1). Transcervical saline amnioinfusion might relieve variable decelerations during labour (level of evidence 3). Prophylactic amnioinfusion for intrapartum oligohydramnios reduces fetal heart rate abnormalities and overall rates of caesarean deliveries (level of evidence 2). Acute tocolysis may be helpful in cases of intrapartum fetal distress related to uterine hyperactivity (level of evidence 2).
Conclusion: Early amniotomy and high doses of oxytocin may both increase the risk of fetal heart rate anomalies, but are both useful for avoiding prolonged labour. More research is needed to attempt the impact of different labour managements and intrauterine resuscitation techniques on neonatal outcomes.