CTG
Cardiotocography (CTG) records pressure changes in the uterus using internal or external pressure transducers
The normal fetal heart rate varies between 100-160 / min
| Feature | Description | Causes |
|---|---|---|
| Baseline bradycardia | Heart rate < 100 /min | Increased fetal vagal tone, maternal beta-blocker use |
| Baseline tachycardia | Heart rate > 160 /min | Maternal pyrexia, chorioamnionitis, hypoxia, prematurity |
| Loss of baseline variability | < 5 beats / min | Prematurity, hypoxia |
| Early deceleration | Deceleration of the heart rate which commences with the onset of a contraction and returns to normal on completion of the contraction | Usually an innocuous feature and indicates head compression |
| Late deceleration | Deceleration of the heart rate which lags the onset of a contraction and does not returns to normal until after 30 seconds following the end of the contraction | Indicates fetal distress e.g. asphyxia or placental insufficiency |
| Variable decelerations | Independent of contractions | May indicate cord compression |
As per NICE guidelines; the following would warrant continuous CTG monitoring if any of the following are present or arise during labour;