Maternal oxygen administration for fetal distress
Abstract
Background
Maternal oxygen administration has been used in an attempt to lessen fetal distress by increasing the available oxygen from the mother. This has been used for suspected fetal distress during labour, and prophylactically during the second stage of labour on the assumption that the second stage is a time of high risk for fetal distress.
Objectives
The objective of this review was to assess the effects of maternal oxygenation for fetal distress during labour and to assess the effects of prophylactic oxygen therapy during the second stage of labour on perinatal outcome.
Search methods
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2007) and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 3).
Selection criteria
Randomized trials comparing maternal oxygen administration for fetal distress during labour and prophylactic oxygen administration during the second stage of labour with a control group (dummy or no oxygen therapy).
Data collection and analysis
Both review authors assessed eligibility and trial quality. Data were extracted, checked and entered into Review Manager software. For dichotomous data, we calculated relative risks (RR) and 95% confidence intervals (CI). For continuous data, we calculated weighted mean differences and 95% CI.
Main results
We located no trials addressing maternal oxygen therapy for fetal distress. We included two trials which addressed prophylactic oxygen administration during labour. Abnormal cord blood pH values (less than 7.2) were recorded significantly more frequently in the oxygenation group than the control group (RR 3.51, 95% CI 1.34 to 9.19). There were no other statistically significant differences between the groups. There were conflicting conclusions on the effect of the duration of oxygen administration on umbilical artery pH values between the two trials.
Authors' conclusions
Implications for practice
There is not enough evidence to support the use of prophylactic oxygen therapy for women in labour, nor to evaluate its effectiveness for fetal distress.
Implications for research
In view of the widespread use of oxygen administration during labour and the possibility that it may be ineffective or harmful, there is an urgent need for randomized trials to assess its effects.
PICOs
Plain language summary
Maternal oxygen administration for fetal distress
Too little evidence to show whether oxygen administration to the woman during labour is beneficial to the baby.
Some babies show signs of distress, such as unusual heart rates or the passing of a bowel motion (meconium) during their mother's labour. This may be caused by a lack of oxygen passing from the woman to the baby through the placenta. Sometimes, women may be encouraged to breathe extra oxygen through a facemask (oxygen administration) to increase the oxygen available to the unborn baby. A review of two trials found too little evidence to show whether oxygen administration to the woman during the second stage of labour is beneficial to the baby. No trials of oxygen administration when the baby is showing signs of distress were found. Further research is needed.
