Module 6 - Pregnancy and fetal monitoring

Question 1

How to measure things before labor

Answer 1

CTG external
EHG-> non invasive
ECG -> non invasive ECG

Question 2

how to measure during labor

Answer 2

ECG
tocodynamometer
intrauterine pressure measurement
EHG

Question 3

After birth:

Answer 3

ECG
impedance pneumogaphy
pulse oximetry (heart rate and saturation)

Question 4

Describe how contractions may affect the fetal heart rate

Answer 4

When there is a small return of blood, there is fast deceleration

prolonged contraction, wide deceleration sign of distress

blood pushed from placenta to fetus, heart rate goes up

Question 5

CTG explain it

and how is it measured

Answer 5

CTG measures fetal heart rate and uterine contractions simultaneously
Electrical activity -> development of tension -> uterus more convex -> cervix dilates

Can be measured with an internal pressure catheter

or with a tocodynamometer
electrodes on the belly

Question 6

Explain three methods to measure fetal heart rate and discuss for each the limitations

Answer 6

Tocodynamometer is inaccurate

internal pressue catheter is very invasive

ECG is non-invasive but very sensitive to movement

Question 7

Electrohystereography

Answer 7

Non-invasive, inexpensive, long term monitoring

measures electrical activity that drives uterine contractions. Activity of the myocardium

can see the cause of contraction

it is hard to interpret the signals, works only in a small area

Question 8

How does non-invasive fetal ECG work

Answer 8

non invasive electrophysiological monitoring

you also get maternal electrocardiogram, external sources, baseline wander, abdominal electromyogram.

Need to use adaptive template subtraction and adaptive Kalman filtering

Spectral analysis of heart rate variabiliy
-> can show activity of the central nervous system, give signs of stress