The principal aim of intrapartum fetal surveillance is to prevent adverse perinatal outcomes arising from fetal metabolic acidosis/cerebral hypoxia related to labour. Many factors contribute to the development and severity of an asphyxial injury and the relationship between metabolic acidosis and cerebral damage is complex. The degree of tissue damage and subsequent injury does not necessarily relate directly to the extent of fetal metabolic acidosis arising during labour.
Most often damage is actually sustained during pregnancy i.e. prior to labour, rather than arising during labour and delivery.
The practice of fetal surveillance during labour would be expected to:
Monitoring the health of the fetus during labour is crucial and important in modern maternity care. Traditionally, this was undertaken by simple regular auscultation of the fetal heart with a stethoscope/fetoscope/pinard. However, this approach was considered by many to be inadequate, particularly for high-risk pregnancies. Therefore, in an effort to reduce the incidence of intrapartum fetal mortality and morbidity, the use of intrapartum electronic fetal monitoring (EFM), particularly continuous CTG, has steadily increased over the last few decades.
The use of CTG for intrapartum fetal surveillance has now become widely used in practice without robust randomised controlled trial (RCT) evidence to support it. The RCTs of continuous CTG which have been undertaken have suggested that its use is not associated with statistically significant improvements in long-term neonatal outcomes such as cerebral palsy. It is associated with significantly increased rates of (unnecessary) operative delivery. Concerns about maternal hazards and small/absent perinatal benefit have led some centers to advice against the routine use of continuous CTG for low risk labours.
Interpretation of CTG is also complex and one need to be able to identify when to intervene with changes in the CTG tracing. Ability and knowledge to identify high risk antenatal cases and to include intrapartum risk is also important factors to include when one is to interpret a CTG tracing.