Assessment of Foetal Wellbeing Flashcards
(35 cards)
What are the US parameters used in foetal surveillance?
- Foetal biometry
- AFI
- Biphysical profile
- Dopplers
What is foetal biometry?
-Head circumference
-Abdominal circumference
-Femur length
Involves absolute and serial measurements.
What is the amniotic fluid index?
Sum of the vertical depth of amniotic fluid in each of the four quadrants.
N: 7-20
What are the components of foetal activity assessed on US?
- Body movements
- Breathing movements
- Tone
What is the biophysical profile of the foetus on US?
5 parameters, 2 points each. 8/10+ = reassuring
- Body movements
- Breathing movements
- tone
- Amniotic fluid index
- CTG
What is assessed on doppler US?
- Umbilical artery (waveform)
- MCA
What is the significance of the umbilical artery waveform?
- Raised SDR, absent EDF, then reversed EDF a/w
- progressive deterioration in placental gas exchange
- evidenced by stepwise increase in perinatal mortality
Normal CTG baseline?
110-160bpm
Normal CTG variability?
5-25bpm
Normal CTG accelerations?
15bpm for 15s
Normal CTG decelerations?
No ominous decelerations
What are the abnormal CTG variability patterns?
- INCREASED (>25bpm): hypoxia
- REDUCED (3-5bpm): sick (hypoxia), sleeping, sedated, submature (SSSS)
- ABSENT
Causes of sedation as detected by non-reactive, reduced variability CTG?
- sedatives
- anti-HT
- anti convulsants
What are the characteristics of early decelerations?
RARE – Timing: simultaneous with contraction, uniform, repetitive – Shape: Gradual onset and recovery – Depth: Almost invariably shallow – Cause: Head compression
Receptor associated with early decelerations?
Pain receptor
What are the characteristics of late decelerations?
– Timing: Uniform, repetitive, begin after contraction onset, recover after contraction complete
– Shape: Gradual onset and recovery
– Depth: May be deep or almost imperceptively shallow
– Cause: Hypoxia
What are the characteristics of variable decelerations?
– Timing: Variable, but usually simultaneous with contraction, repetitive or intermittent
– Shape: Sudden onset and recovery
– Depth: Mild (<60bpm for <60 secs), Mod (>60bpm OR >60 secs), Severe (> 60bpm AND >60 secs)
– Cause: Cord compression
How are variable decelerations classified?
-Mild: 60 bpm OR > 60 secs -Severe > 60 bpm AND > 60 secs OR Delayed Recovery OR Rebound Tachycardia
What are the characteristics of prolonged decelerations?
- Shape: sustained bradycardia
- Timing: more than 2 mins
- Cause: sustained hypoxia
- Receptor: chemoreceptor
what are causes of sudden severe foetal hypoxia?
- Cord compression
- Maternal hypotension
- Sustained uterine contraction
- Placental abruption
How are antenatal CTGs classified and what is the implication of each?
- Reactive: (reassured). Normal baseline, normal variability, accelerations, no adverse decelerations.
- Non-reactive (investigate). No accelerations, reduced variability.
- Critical (DELIVER - C/S). Late decelerations, absent variability, sinusoidal pattern.
How to investigate antenatal non reactive CTG?
Is it due to hypoxia??
- Foetal stimulation tests e.g. VAST
- Doppler US (UA waveform, MCA PSV)
- Biophysical profile
Characteristics of the gynaecoid pelvis?
Classic female pelvis.
- Posterior sagittal diameter of inlet only slightly shorter than anterior sagittal diameter
- posterior pelvis rounded and wide
- sidewalls straight
- spines not prominent
What is mentum presentation?
Face presentation with foetal head hyperextended so occiput in contact with foetal back; chin (mentum) presenting.
