Amnioinfusion for meconium-stained liquor in labour

Cochrane Review by Hofmeyr GJ, Xu H

This record should be cited as: Hofmeyr GJ, Xu H. Amnioinfusion for meconium-stained liquor in labour. Cochrane Database of Systematic Reviews 2010, Issue 1. Art. No.: CD000014. DOI: 10.1002/14651858.CD000014.pub3.

ABSTRACT

Title

Amnioinfusion for meconium-stained liquor in labour

Background

Amnioinfusion is thought to dilute meconium present in the amniotic fluid and so reduce the risk of meconium aspiration.

Objectives

To assess the effects of amnioinfusion for meconium-stained liquor on perinatal outcome.

Search strategy

We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (May 2009).

Selection criteria

Randomised trials comparing amnioinfusion with no amnioinfusion for women in labour with moderate or thick meconium-staining of the amniotic fluid.

Data collection and analysis

Two review authors assessed eligibility and trial quality, and extracted data, independently.

Main results

Thirteen studies of variable quality (4143 women) are included. Subgroup analysis was performed for studies from settings with limited facilities to monitor the baby’s condition during labour and intervene effectively, and settings with standard peripartum surveillance. Settings with standard peripartum surveillance: there was considerable heterogeneity for several outcomes. There was no significant reduction in the primary outcomes meconium aspiration syndrome, perinatal death or severe morbidity, and maternal death or severe morbidity. Therewas a reduction in caesarean sections (CSs) for fetal distress but not overall.Meconium below the vocal cords diagnosed by laryngoscopy was reduced, as was neonatal ventilation or neonatal intensive care unit admission, but there was no significant reduction in perinatal deaths or other morbidity. Planned sensitivity analysis excluding trials with greater risk of bias resulted in an absence of benefits for any of the outcomes studied.Settings with limited peripartum surveillance: two studies (855 women) were included. In the amnioinfusion group there was a reduction in CS for fetal distress and overall;meconium aspiration syndrome (RR 0.25, 95%CI 0.13 to 0.47), and neonatal ventilation or neonatal intensive care unit admission; and a trend towards reduced perinatal mortality (RR 0.37, 95% CI 0.13 to 1.01). In one of the studies, meconium below the vocal cords was reduced and, in the other, neonatal encephalopathy was reduced.

Authors' conclusions

Amnioinfusion is associatedwith substantive improvements in perinatal outcome only in settingswhere facilities for perinatal surveillance are limited. It is not clear whether the benefits are due to dilution of meconium or relief of oligohydramnios. In settings with standard peripartum surveillance, some non-substantive outcomes were improved in the initial analysis, but sensitivity analysis excluding trials with greater risk of bias eliminated these differences. Amnioinfusion is either ineffective in this setting, or its effects are masked by other strategies to optimise neonatal outcome. The trials reviewed are too small to address the possibility of rare but serious maternal adverse effects of amnioinfusion.

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