Electronic fetal monitoring (EFM) is performed to decrease perinatal morbidity and mortality and to avoid unnecessary operative deliveries. Delivery is a process where lack of oxygen and acidosis is part of the normal course of events - uterine contractions decrease maternal blood stream to the placenta. The goal is to identify fetuses at an unacceptable high risk.
CTG (cardiotocography) was introduced in the 1960s and is registration of the fetus' heart rate with simultanous registration of uterine contractions.
There have been performed several RCTs which all have failed to show that CTG improves neonatal outcome. CTG has turned out to have high sensitivity but lower specificity. This has led to an increase in the number of operative deliveries without corresponding decrease in perinatal morbidity and mortality due to hypoxic events during delivery.
CTG alone has turned out to be an inadequat method for fetal monitoring, and new methods have developed. Among these are fetal blood sampling, pulse oxymetri and STAN. Fetal blood sampling are widely used in Norway together with CTG. Pulse oxymetri is not currently used in Norway.
STAN is a method where the fetal ECG is registered by a scalp electrode and the ST-segment is automatically analysed. One then intervenes by well-defined clinical guidelines. Two RCTs show that use of STAN reduces the number of hypoxic events during delivery without increasing the number of operative deliveries. STAN is used by 15 delivery wards in Norway, but this number is hoped to increase in the years to come.