Foetal scalp blood sampling and ST-analysis of the foetal ECG for intrapartum foetal monitoring: a restricted systematic review

BACKGROUND: To investigate if foetal scalp blood sampling (FBS) is useful in preventing foetal metabolic acidosis in labour when ST-analysis of the foetal ECG (STAN ® ) is already being used as a second line technique for intrapartum foetal monitoring with cardiotocography (CTG). DESIGN: Restricted systematic review. METHODS: Based on a literature search in July 2019, a restricted systematic review was performed. Studies comparing CTG+STAN ® +FBS with CTG+STAN ® , CTG+FBS or CTG only were included. Observational studies allowing FBS in addition to STAN ® reporting the indications, results and neonatal outcomes were included as well. RESULTS: Five randomised controlled trials (RCT) and seven observational trials were analysed. Based on the analysis of data coming from one RCT, FBS identifies foetal acidosis in 9.9% when performed in specific situations. Similarly, in observational trials it was found that in up to 10% of cases where STAN ® registration was less reliable, FBS suggested foetal acidosis. However, there is no evidence that FBS in these cases was capable of preventing metabolic acidosis or its neurological consequences. CONCLUSION: Based on the available literature, no recommendations in favour of combining FBS with STAN ® monitoring can be made.