Cardiotocography (CTG) Flashcards
what does CTG do?
records pressure changes in the uterus using internal or external pressure transducers
what is the normal fetal heart rate?
100-160/min
what is baseline bradycardia?
HR < 100/min
what causes baseline tachycardia?
- increased fetal vagal tone
- maternal BB use
what is baseline tachycardia?
HR >160/min
what causes baseline tachycardia?
- maternal pyrexia
- chorioamnionitis
- hypoxia
- prematurity
what does loss of baseline variability mean?
< 5 beats /min
what are the causes of loss of baseline variability?
- prematurity
- hypoxia
what is an early deceleration?
deceleration of the heart rate which commences with the onset of a contraction and returns to normal on completion of the contraction
what are the causes of an early deceleration?
usually an innocuous feature and indicates head compression
what is a late deceleration?
deceleration of the heart rate which lags the onset of a contraction and does not return to normal until after 30 seconds following the end of the contraction
what do late decelerations indicate?
fetal distress e.g. asphyxia or placental insufficiency
what are variable decelerations?
independent of contractions
what do variable decelerations indicate?
cord compression
late decelerations present on CTG trace, what do you need to do next?
late decelerations are a pathological finding!
urgent fetal blood sampling to assess for fetal hypoxia and acidosis
if fetal acidosis –> urgent delivery
