Case 80: Labour

 CASE 80: LABOUR

History

A 22-year-old woman in her second pregnancy has arrived on the labour ward at 38 weeks

3 days. She had a normal delivery 18 months ago. This pregnancy has been complicated by

persistent vomiting until 20 weeks and more recently by anaemia. She reports contractions

commencing approximately 4 h ago. She took paracetamol at home and tried to relieve the

pain with a bath, but now feels she cannot cope with the pain.

She had a show 2 days ago but has had no bleeding since then and has not noticed any vaginal

leak. She has felt the baby moving normally all day.

Examination

The blood pressure is 110/58 mmHg and heart rate is 98/min. The presentation is cephalic

with 2/5 palpable abdominally. Uterine contractions are palpable and the uterus is nonirritable. On vaginal examination the cervix is 5 cm dilated and the head is 1 cm above the

ischial spines. The fetal position is right occipitotransverse with mild caput and moulding. The membranes are intact but rupture spontaneously during examination, with clear

liquor draining.

The woman requests an epidural for pain relief and is therefore commenced on continuous

cardiotocograph monitoring. After 20 min you are called in to review the situation.

INVESTIGATIONS

The CTG as you walk in is shown in Fig. 80.1.

Questions

• Describe the CTG.

• What are the possible causes of this CTG?

• What management would be appropriate now?

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Figure 80.1 Cardiotocograph.100 Cases in Obstetrics and Gynaecology

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ANSWER 80

CTG interpretation

The initial 15 min of CTG shows a baseline of 145/min with normal variability (12/min) and

no visible acceleration or decelerations. Following this there is a drop in fetal heart rate to

70/min for 7 min before gradual recovery to 125/min. Contractions are 2 in 10 until the tocograph becomes unreadable.

This is a previously low-risk pregnancy and this CTG shows a fetal bradycardia (reduction in

baseline heart rate to below 100/min). In many cases no cause is identified.

! Causes of fetal bradycardia

• Placental abruption

• Uterine rupture

• Maternal hypotension (e.g. after epidural insertion)

• Bleeding vasa praevia

Management

The ‘rule of 3s’ should be employed in managing this woman:

• If the deceleration has not recovered at 3 min call for help.

• If the deceleration has not recovered at 6 min transfer to theatre and prepare for

immediate delivery.

• If the deceleration has not recovered at 9 min deliver immediately by category one

(‘crash’) caesarean section (if immediate instrumental vaginal delivery is not possible). This will usually involve general anaesthetic unless an effective spinal anaesthetic is achievable by an experienced anaesthetist in a similar time.

The labour ward theatre team should be called (including anaesthetist, obstetric registrar,

paediatrician, midwife in charge, theatre staff) and the woman transferred to the operating theatre. On occasion the bradycardia recovers as preparation is underway for the caesarean, in which case the plan may be reviewed. Otherwise the baby should be delivered

immediately.

In this case the bradycardia did not recover and the baby was delivered within 12 min of the

decision being made. No cause was found for the bradycardia at caesarean section.

INVESTIGATIONS

The umbilical artery cord blood analysis at delivery was:

Artery Vein

pH 7.06 7.23

pCO2 8.20 mmHg 6.30 mmHg

Base excess –6.4 mmol/L –5.2 mmol/LCase 80: Labour

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The baby initially made poor respiratory effort and had a heart rate less than 100/min, but

recovered quickly with drying and warming. The Apgar score for the baby was 5 at 1 min and

9 at 5 min.

KEY POINTS

• A prolonged bradycardia (>6 min) is an indication to transfer a woman to theatre

for consideration of immediate delivery if the heart rate has not then recovered

by 9 min.

• There is no place for a fetal blood sample in the management of fetal bradycardia.

• A cause is not always found for an abnormal CTG.