Assessment of foetal well-being (Foetal heart rate ( Oscillation: Short…
Assessment of foetal well-being
Electronic monitoring (CTG), - OCT – oxytocin challenge test , NST – NON-Stress test, BIOPHYSICAL PROFILE (Manning TEST) , Ultrasonography (Doppler) , Pulse-oximetry, Gasometry, Foetal ecg
Foetal heart rate
! 110-150 heart beats per minute – normocardia
! >150 heart beats per minute – tachycardia
! <110 heart beats per minute – bradycardia
Reasons of bradycardia:
pressure on foetal head
Foetal haemmorhgage (for example damage in vasa previa)
Decline in foetal compensation abilities in cases of hypoxia and acidosis (terminal bradycardia)
Reasons for chronic bradycaria:
Reasons for tachycardia:
Medications – beta-agonists and atropine,
hypoxia accompanied by late decelerations
Short-term changes in foetal heart rate are called oscillations.
silent – 0-5 heart beats per minute
narrow – 5-10 heart beats per minute
undulatory (the correct one) – 10-25 heart beats per minute
leaping - >25 heart beats per minute
Temporary increase in foetal heart rate of 15 heart beats per minute or more as compared with basic foetal heart rate. lasts for 15 seconds or more.
Temporary decrease in foetal heart rate of 15 heart beats per minute or more as compared with basic foetal heart rate. lasts for 15 seconds or more.
Umbilical cord collision
The closing of the umbilical vein and decrease in foetal blood pressure,
Complete stop in umbilical circulation – sudden incrase in pressure,
Second decrease in blood pressure (umbilical arteries open up),
Umbilical circulation goes back to normal.
Signs of placental insufficiency
low foetal activity – decreased number of accelerations and narrow oscillations / silent – Hypoxia
NST (Non Stress Test)
30 minutes CTG reading plus foetal movement monitoring
The test is reactive when there are 2 or more accelerations during 30 minutes, normocardia, foetal movements are registered, oscillation is of more than >10 heart beats per minute.
The test is non reactive when: foetal movements and oscillation are not observed, oscillation is of less than <10 heart beats per minute.
The test is inconclusive if there is one acceleration plus foetal movements, lack of full acceleration criteria, oscillations are of less than <10 heat beats per minute, tachycardia/ bradycardia
Non-reactive – the test needs to be prolonged or repeated after one hour, if the reading is still non-reactive or if decelerations take place further foetal well-being monitoring needs to be started (OCT test, doppler ultrasonography)
Oxytocin challenge test (OCT)
foetal heart rate assessment during uterine contractions.
Intravenous oxytocin infusion.
The test is viewed as successful when there are 3 contractions within 10 minutes.
Contraindications to OCT
classical C-section before,
Danger of premature labour
negative – contractions are present, the oscillation is correct, no decelerations, reactive reading,
positive – late decelerations > 50% contractions,
inconclusive – late decelerations < 50% contractions ,
failed – no contractions.
Foetal biophysical profile – Manning test
30 minutes observation of foetal activity in real time with the use of ultrasonography together with conducting an NST.
foetal breathing movements
amniotic fluid volume
SpO2 > 30% foetal oxygenation within norm
SpO2 ~ 30% borderline, intensive CTG monitoring
SpO2 < 30% foetal well-being needs to be verified with the use of gasometry or the labour must be ended