The use of STAN monitoring in the labour ward

Continuous intrapartum cardiotocography (CTG) augmented by fetal ECG ST segment analysis (STAN) has the potential to reduce the rates of neonatal metabolic acidosis and obstetric interventions. STAN was introduced at Ninewells Hospital, Dundee in October 2007. Data were collected prospectively from all women who received continuous intrapartum CTG and STAN between 1 October 2007 and 31 March 2008. A total of 253 women had continuous CTG and STAN. The median number of ST events was one (range = 1-32). Most (556/719, 77%) ST events were associated with a normal CTG; 46/144 (32%) patients with an ST event required immediate action. Three of the 253 (1.2%) women were delivered based on an ST event with a normal CTG; four (1.5%) had severe neonatal metabolic acidosis and all four cases had intrapartum ST events and were not managed according to STAN guidelines. ST events are common but the majority of ST events require no action. The high incidence of false-positive ST events might have contributed to the failure to act when a significant ST event occurred.