FETAL OXYGEN-SATURATION MONITORING IN LABOR - AN ANALYSIS OF 118 CASES

Fetal oxygen saturation (FSpO(2)) was recorded during labour to determ ine the relationship between FSpO(2) and indicators of fetal well-bein g, including umbilical blood gases, xanthine (X), hypoxanthine (Hx) an d Apgar scores. This is one of the largest reported series of fetal pu lse oximetry, with 118 fetuses monitored for over 329 hours. Mean FSpO (2) for all cases was 46.9% (SD=9.1%). There was no correlation betwee n FSpO(2) during the last 10 minutes of monitoring and arterial pH, Hx or X. A mean FSpO(2) greater than or equal to 30% was associated with a 5 minute Apgar score of greater than or equal to 7 in the majority of cases. One fetus had a mean FSpO(2) <30% during the final 10 minute s of monitoring and an umbilical arterial pH<7.20, while there were 10 fetuses with an umbilical arterial pH<7.20, and mean FSpO(2) greater than or equal to 30%. As these numbers are small, a larger series is n ecessary to further characterize the small number of fetuses who are s ignificantly hypoxic.