CTG

Question 1

CTG

Answer 1

Monitoring fetus antenatal and intrapartum
- High level of sensitivity but low specificity, meaning that they are useful for identifying and monitoring well fetuses but don’t always tell us what’s happening with an unwell/unhappy fetus

Question 2

Baseline Variability

Answer 2

• Baseline FHR 100-160 bpm
  Monitor fluctuations of the FHR
  Normal Variability = 6-25bpm from baseline
  Reduced Variability = 3-5bpm from baseline
  Absent Variability = <3bpm from baseline
  Increased (salutatory) = >25bpm from baseline

Question 3

Accelerations

Answer 3

A transient increase in FHR of 15bpm or more above the baseline and lasting only 15 seconds. accelerations in preterm fetuses may have less of an amplitude

Question 4

Decelerations

Answer 4

A transient decrease in 15bpm below the baseline lasting more than 15 seconds

Question 5

Decelerations continued

Answer 5

Early = Benign and seen usually with sleep pattern. Often with contraction. Uniformed in shape and start and finish with contraction. The normal response to fetal head compression (increased ICP)

Question 6

Decelerations continued

Answer 6

Variable = The significance of a variable deceleration depends on the whole clinical picture. Other pertinent factors will change the interpretation of a CTG. Can be caused by cord compression, typically a normal physiological response but can be pathological. Variable timing, depth and duration. Rapid onset and recovery

Variable decelerations associated with other non-reassuring signs will be a complicated - variable = indicates fetal hypoxia and include two of the following

• rising baseline FHR or fetal tachycardia
• reduced or absent baseline variability
• large amplitude or lasting >60 seconds
• slow return to baseline after contraction

Question 7

Decelerations continued

Answer 7

Prolonged = lasting 90 seconds to 5 minutes - no more

• caused by hypoxia
• reflect fetal environment rather than the fetal condition
• may result from prolonged contraction, epidural insertion, supine hypotension, uterine hyperstimulation, abruption or VE

Question 8

Decelerations continued

Answer 8

Late = caused by contractions and the presence of hypoxia. Start after the commencement of a contraction, the peak of the decel is more than 20secs after the peak of the contraction, significant

Question 9

State the normal, reassuring feature of a CTG in antenatal and intrapartum

Answer 9

ANTENATAL
- baseline between 110 - 160bpm
- 6-25bpm baseline variability
- 2-20 minute accelerations
- no decelerations
INTRAPARTUM
- accelerations more than 2 in 20 minutes
- normal baseline variability
- no decelerations
- baseline between 100-160bpm

Question 10

List the controls of the fetal heart rate

Answer 10

• continuous interaction between PNS and SNS
• SA nodes
• Autonomic nervous system
• CRC
• Baroreceptors
• Chemoreceptors
• Stress release (catachalmines)

Question 11

List two maternal and fetal reasons for CTG

Answer 11

Maternal:
1) IOL
2) Epidural 
3) Essential or maternal hypertension
Fetal:
1) IOL
2) abnormal heart beat
3) decreased fetal movement
4) meconium
5) post dates