Amnioinfusion for meconium-stained liquor in labour

Hofmeyr GJ, Xu H

Published Online:

August 8, 2010

Amnioinfusion is not beneficial for babies releasing medium to heavy meconium during labour, except in settings with limited facilities to monitor the baby's condition during labour.

A bowel movement (meconium) from the unborn baby during labour can enter the baby's lungs, causing breathing difficulties after birth. Extra liquid can be injected through the woman's vagina or abdomen into the womb (amnioinfusion) to provide more liquid to dilute the meconium and surround the baby. The review of 13 trials (4143 women) found that amnioinfusion with a salt (saline) solution is beneficial for babies only in settings in which babies are at high risk due to limited monitoring facilities. Further research into the effects on women is needed.

Abstract (click to read)

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. There was 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 associated with substantive improvements in perinatal outcome only in settings where 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.

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

Assessed as up to date:

November 11, 2009

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Primary Review Group:

Pregnancy and Childbirth Group

Health topics:

Pregnancy & childbirth > Fetal compromise during labour > Treatment

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

Amnioinfusion for meconium-stained liquor in labour

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