Fetal oxygen saturation during labour

Abstract

Objective: To derive oxygen saturation by pulse oximetry (SpO 2) values at each cervical dilatation in labour in fetuses with normal neonatal outcome. Participants: One hundred and forty-five women at term in established labour with ruptured membranes and cervical dilatation at least 2 cm who had normal delivery outcome. The infants had 5 minute Apgar scores ≤7, birthweight ≤2500 g, umbilical cord artery pH ≤7-15 and did not require assisted ventilation or admission to neonatal intensive care. Methods: Women were monitored continuously with cardiotocography and fetal pulse oximetry using the Nellcor N-400 fetal pulse oximeter and FS-14 fetal oxisensor till delivery. Labour was managed according to established protocol without recourse to SpO 2 readings. Results: There was a wide range of SpO 2 values during labour in fetuses with normal outcome. Mean values averaged 50% ± 10% throughout the first stage of labour, with lower ranges of SpO 2 values above 30%. There was no significant difference in SpO 2 readings at different cervical dilatations in the first stage of labour. Mean SpO 2 values in the last 10 minutes before delivery were also not significantly different from those in the first stage of labour. Conclusion: The range of SpO 2 in 115 healthy fetuses during normal labour was wide, but always above 30%. There was no trend of SpO 2 values in this study of 115 fetuses with normal neonatal outcome.