Maternal oxygen administration for fetal distress

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 (22 October 2012) and searched reference lists of retrieved studies. 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.