CTG & DR keywords

What is a normal baseline FHR?

110 - 160bpm

What is the definition of a baseline FHR?

The average FHR within 10 minutes

What is the definition of tachycardia?

Baseline FHR > 160bpm

What is the definition of bradycardia?

Baseline FHR < 110bpm

What are 5 causes of fetal tachycardia?

Fetal hypoxia

Chorioamnionitis

Hyperthyroidism

Fetal or maternal anaemia

Fetal tachyarrthymia

What are 3 causes of fetal bradycardia?

Postdate gestation

Occiput posterior or transverse presentation

If prolonged, is a sign of severe hypoxia

What is the definition of prolonged bradycardia?

FHR < 80bpm for more than 3 minutes

What is the most desirable fetal position?

Occiput anterior (baby’s face facing mum’s spine)

What is baseline variability?

the variation of fetal HR from one beat to the next, measured in bpm – normal variability is 5 – 25 bpm

What are 6 causes of reduced variability?

Fetal sleeping

Fetal acidosis

Fetal tachycardia

Drugs: opiates, benzodiazepines, magnesium sulphate

Prematurity

Congenital heart abnormalities

Accelerations (including DR definition) - total 2

1. An increase in FHR greater than 15bpm for greater than 15 seconds

2. DR: an increase in FHR greater than 10bpm lasting longer than 15 seconds

Decelerations (including DR definition) - total 3

1. A decrease in FHR greater than 15bpm for greater than 15 seconds

2. DR: a decrease in FHR of at least 20bpm for longer than 30 seconds or at least 10bpm lasting longer than 60 seconds

What is the definition of short-term variation (STV)?

Is a computerised measure of the micro-fluctuations of the fetal heart, and examines the variability of the FHR from beat to beat

What is the definition of minute range?

The DR calculates minute range which is the sum of the absolute value of the maximum deviation above & below the baseline in a given minute

What is the definition of the long-term variation (LTV)?

Is equivalent to traditional baseline variability, and is is the mean minute range for the entire recording.

What is the definition of failure time/signal loss?

The number of invalid fetal heart pulsations and removed epochs within the trace