Assessment of foetal wellbeing (CTG)

Question 1

What should you ask the mother about on Hx to assess foetal wellbeing?

Answer 1

Foetal movements

Question 2

When should a mother be able to start feeling foetal movements?

Answer 2

Between 18-20 weeks

Question 3

1 Ex for assessing foetal wellbeing?

Answer 3

Symphyseal-fundal height. Length should match no. weeks gestation

Question 4

Name 4 foetal biometry measurements on U/S

Answer 4

Head circumference
Biparietal diameter
Abdominal circumference
Femur length

Question 5

What does a smaller abdominal:head ratio on foetal biometry indicate about the foetus?

Answer 5

It’s starving!

Question 6

What does the amniotic fluid index measure on U/S

Answer 6

Vertical depth of amniotic fluid

Question 7

What is better: a flexed or extended foetus in utero?

Answer 7

Flexed; extension indicates illness

Question 8

Name the 6 parameters that make up the biophysical profile of a foetus

Answer 8

Foetal body movements
Foetal breathing
Foetal HR
Amniotic fluid index
Foetal tone
CTG

Question 9

What two vessels are often measured by Doppler U/S in pregnancy, and what can they show? At what stage of pregnancy are they measured? Name 3 indications to use Doppler U/S

Answer 9

Umbilical artery and Middle Cerebral Artery - useful in measuring foetal hypoxia. Measured in 3rd trimester.

Indications - any scenario where there’s a risk of IUGR or poor perinatal outcome:

Maternal - DM, renal disease, HT
Foetal - IUGR, reduced foetal movements, oligo/polyhydramnios, multiple pregnancy

Question 10

What does a CTG measure?

Answer 10

Variation in foetal HR over time

Question 11

What are the 4 features of a CTG? What are normal values for them?

Answer 11

Baseline HR - 110-160bpm
Variation - 5-25bpm
Acceleration - 2x 15bpm accelerations in 20 minutes
Deceleration - none

Question 12

What do increased, reduced and absent variability indicate on a CTG?

Answer 12

Increased - anaemia
Reduced - sleeping, sedated, sick, submature (premature)
Absent - Severe hypoxia

Question 13

What does a sinusoidal pattern of variability indicate on CTG?

Answer 13

Severe foetal anaemia

Question 14

What is an early deceleration and what does it indicate?

Answer 14

Deceleration simultaneous with contraction. Indicates head compression during labour

Question 15

What is a late deceleration and what does it indicate?

Answer 15

Deceleration that peaks after peak of contraction. Indicates foetal hypoxia (already hypoxic foetus will peripherally vasoconstrict during contraction = HR will drop to maintain BP)

Question 16

What is a variable deceleration and what does it indicate?

Answer 16

Deceleration simultaneous with contraction but with rapid onset and recovery. Indicates cord compression during late labour

Question 17

What is a prolonged deceleration and what does it indicate?

Answer 17

Deceleration > 2 minutes. Indicates sustained hypoxia

Question 18

Give 4 causes of sudden severe foetal hypoxia

Answer 18

Cord compression
Maternal hypotension
sustained uterine contraction
Placental abruption

Question 19

What is a reactive, non-reactive and critical CTG? What should you do in each case?

Answer 19

Reactive = normal (normal baseline, variability, accelerations, no decelerations). Continue with intermittent CTG or auscultation.

Non-reactive = reduced variability, no accelerations. Investigate for hypoxia (Doppler U/S, biophysical profile), and start continuous CTG

Critical - late decelerations, absent variability, sinusoidal pattern. Deliver via C/S, unless cervix already fully dilated and head is low