The reliability of fetal pulse oximetry: The effect of fetal oxygen saturation below 30% on perinatal outcome

Abstract 

Objectives

The objective of this prospective study was to determine the reliability of fetal pulse oximetry (FPO) in cases of abnormal fetal heart rate (FHR) pattern and fetal oxygen saturation (FSpO₂) below 30%.

Study design

Three hundred and one deliveries complicated by abnormal FHR pattern were monitored with both CTG and FPO. Cases of FSpO₂ values below 30% (n=52) formed the study group and those above 30% (n=249) were the control group. pH and base excess (BE) in the umbilical cord artery, 5-min Apgar score, and pH and BE in the newborn were measured and compared. Statistical analysis included the Epi info 2002 program, Chi-squared test, and linear regression.

Results

FSpO₂ values were consequently below 30% in 52 and above 30% in 249 cases. When FSpO₂ values were below 30%, umbilical pH was significantly lower than in controls (P<0.01), while other parameters were not significantly different. If the time interval between the measurement of the first low (<30%) FSpO₂ value and delivery did not exceed 32.4±2.5min, umbilical pH and Apgar scores did not show fetal acidosis.

Conclusion

Our findings suggest that FPO is a reliable method of estimating fetal condition and may help reduce the number of cesarean sections performed due to abnormal FHR tracings.

Keywords: Fetal pulse oximetry, Fetal oxygen saturation, Perinatal outcome