Cardiotocography (CTG) monitors the fetal heart rate and uterine contractions during pregnancy. It is used in the third trimester to detect fetal distress. CTG involves placing transducers on the abdomen to record these measurements. Recordings are assessed using the DR C BRAVADO method to analyze characteristics like baseline heart rate, accelerations, contractions, variability, and decelerations. The overall CTG impression is classified as reassuring, suspicious, or pathological based on these features. Continuous CTG is indicated in low-risk pregnancies under certain conditions like meconium staining or abnormal heart rate detected during intermittent monitoring. Studies found continuous CTG may increase instrumental births but did not reduce perinatal mortality or mor

1. OBSTETRIC &GYNAECOLOGY DEPARTMENT
CARDIOTOCOGRAPHY

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 Cardiotocography (CTG) is a test used in pregnancy to
monitor both the fetal heart pattern as well as the
uterine contractions.
 It should only used in the 3rd trimester when fetal neural
reflexes are present.
 Its purpose is to monitor fetal well-being & allows early
detection of fetal distress antenatal or intra-partum.
 An abnormal CTG indicates the need for further invasive
investigation & ultimately may lead to emergency CS

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-Usually every 7 days (i.e. weekly)
-Twice-weekly testing is advocated by some in :
 Post term pregnancy
 Diabetes mellitus
 Fetal growth restriction,
 Gestational hypertension
- Additional testing is performed for maternal
or fetal deterioration regardless of time
elapsed
-Others perform non-stress tests daily or even
more frequently

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6.  The machine used is called cardio-tocograph.
 It involves the placement of 2 transducers on the
abdomen of a pregnant woman: one transducer records
the fetal heart rate using ultrasound beam , the other
transducer records uterine contractions by measuring the
tension of the maternal abdominal wall. This provides
indirect indication of the intrauterine pressure.
 These recordings are blotted on a special paper.
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Internal fetal monitoring
FSE

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 The machine used is called cardio-tocograph.
 It involves the placement of 2 transducers: a
fetal scalp electrode( FSE): an internal fetal heart
monitor , and intrauterine pressure
catheter(IUPC): an internal uterine contraction
monitor
 These recordings are shown on a screen and
may be blotted on a special paper.

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Horizontal Scale
Paper speed is set to 1,2,or 3 cm /minute.
Vertical Scale:
 Sensitivity displays are set to 20 or 30 beats per
minute (bpm) /cm.
 FHR range displays of 30–240 bpm .
 Uterine Activity: Internal 0-100 mmHg
External 0-100 relative units

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 To interpret a CTG you need a structured
method of assessing its various characteristics.
 The most popular method can be remembered
using the acronym DR C BRAVADO
- DR=Define Risk .
- Bra= Baseline Rate
- A= Accelerations
- C= Contractions
- V=Variability
- D= Decelerations
- O= Overall impression

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 You first need to assess if this pregnancy
is high or low risk
 This is important as it gives more context
to the CTG reading ;e.g. If the pregnancy is
high risk, your threshold for intervening
may be lowered.

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High-risk pregnancies:

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 Record the number of contractions present in a 10
minute period - e.g. 3 in 10
 Each big square is equal to 1 minute, so you look
how many contractions occurred in 10 squares
 Individual contractions are seen as peaks on the part
of the CTG monitoring uterine activity
 You should assess contractions for the following:
 Duration – how long do the contractions last?
 Intensity – how strong are the contractions? (assessed using palpation)

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 The baseline rate is the average heart rate of
the fetus in a 10 minute window.
 Look at the CTG & assess what the average
heart rate has been over the last 10 minutes
 Ignore any Accelerations or Decelerations
 A normal fetal heart rate is between 120-160
bpm.

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Reduced variability can be caused by:
1. Fetus sleeping - this should last no longer than 40 minutes – most common cause
2. Fetal acidosis (due to hypoxia) – more likely if late decelerations also present
3. Fetal tachycardia
4. Drugs – opiates, benzodiazipine’s, methyldopa, magnesium sulphate
5. Prematurity – variability is reduced at earlier gestation (<28 weeks)
6. Congenital heart abnormalities

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-Once you have assessed all aspects of the CTG you need to give your
overall impression. The overall impression can be described as either:
 Reassuring
 Suspicious
 Pathological
-The overall impression is determined by how many of the CTG features were
either reassuring, non-reassuring or abnormal. The NICE guideline
demonstrates how to decide which category a CTG falls into:
1Normal CTG= All four features are classified as reassuring.
2Suspicious CTG= One feature is classified as non-reassuring whilethe
remaining features are reassuring
3Pathological CTG= ≥ 2 features non-reassuring, or ≥ 1 feature
classified as abnormal

17. Continuous EFM In Low-risk Women:
Indications:
1. Significant or light Meconium-stained liquor
2. Abnormal FHR detected by intermittent auscultation
(< 110 bpm; or > 160 bpm, or any decelerations after a
contraction.
3. Maternal pyrexia (defined as 38.0 °C once or 37.5 °C on
two occasions 2 hours apart)
4. Fresh bleeding developing in labor
5.Oxytocin use for augmentation
6. The woman’s request.

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Continuous EFM In Low-risk Women:
Evaluation :
 There was a borderline evidence that continuous EFM
were more likely to have an instrumental birth
compared with the auscultation group although there
was no evidence of differences in:
 Augmentation
 Perinatal mortality
 Other neonatal morbidities