7: Abnormal labour Flashcards
In general terms, what can go wrong in the course of labour?
Too early
Too late
Too quick - hyperstimulation
Too slow - failure to progress
Too painful
Malpresentation and/or malposition
Foetal distress
What percentage of women have a normal vaginal delivery?
60%
What percentage of women have a forceps delivery?
15%
What percentage of women have Caesarean sections?
25%
What is malpresentation?
A non-vertex delivery
What is the vertex?
Space between the anterior/posterior fontanelles and parietal eminences
What is malposition?
Non occipito-anterior position
What is the definition of pre-term labour?
< 37 weeks
What is the definition of post-term delivery?
> 42 weeks
Beyond 42 weeks, the risk of what increases exponentially?
Stillbirth
What is a Category 1 Caesarean section?
C section within 30 minutes of diagnosis
Everyone is bleeped to come and help
In which malpresentation does the baby’s feet emerge first?
Breech
What is the risk of a breech birth?
How can this be avoided?
Head gets stuck –> foetal hypoxia
Caesarean section
Apart from breech, what are some other types of malpresentation?
Transverse
Shoulder / Arm
Face
Brow
Which terms are used to describe the position of face presentations?
Mento-anterior
Mento-posterior
Which analgesia is used in obstetric emergencies?
Spinal or general anaesthetic
because they’re quickest acting - spinal is ideal
In general terms, what does failure to progress mean?
Baby isn’t coming out
If the cervix dilates less than ___ in 4 hours, there is failure to progress
< 2cm in 4hrs
What is the station of a baby?
Position of lowest bit of presenting part compared to ISCHIAL SPINES
negative numbers - above spines - not engaged - bad
positive numbers - below spines - good
What is the name of the synthetic oxytocin used to stimulate uterine contractions?
Syntocinon
What tool can be used to view the course of labour?
Partogram
How is fetal distress monitored?
Doppler ultrasound for heart rate
CTG for heart rate
Colour of amniotic fluid
What pattern of foetal heart rate, relative to contractions, indicates foetal distress?
Late decelerations
Foetal heart rate decreases at the onset of a contraction (something to do with their head being compressed)
If that occurs late on in a contraction, it means that the body is reflexively trying to keep HR up due to poor oxygenation - baby is hypoxic
What are the three Ps influencing the success of vaginal delivery?
Power
Passage
Passenger
What does foetal distress mean?
Foetal hypoxia
characteristic CTG patterns
What conditions cause foetal distress?
Placental abruption
Cord prolapse
Uterine rupture
Antepartum haemorrhage
Foetal anaemia
Are early decelerations on CTG normal?
Yes
Baby’s head squashed by uterus during contractions causing vagal bradycardia
Are late decelerations on CTG normal?
No
Indicates foetal hypoxia, because the body is reflexively trying to keep foetal HR up for as long as possible
What is the mnemonic used for interpreting CTGs?
DR C BRAVADO
What does DR C BRAVADO stand for in terms of CTGs?
DR - determine risk
C - contractions
BRA - baseline rate
V - variability
A - accelerations
D - decelerations
O - overall impression
What is CTG?
Cardiotocography
Measurement of foetal heart rate AND uterine contractions, allowing you to compare them
How do you determine the risk of a patient before looking at their CTG?
From history
The ___ and ___ of contractions increase during the course of labour.
number and duration of contractions
What is a normal foetal heart rate?
120 - 160bpm
faster than adults
Is increase in foetal heart rate on examination normal?
Yes
Normal sympathetic response
It’s an example of variability, which is a reassuring sign on CTG
What is variability in terms of a CTG?
Fluctuations in foetal heart rate
Normal and desired, given they’re not too extreme
(Accelerations / decelerations) on a CTG are normal.
accelerations are normal
What kind of decelerations are benign on a CTG?
Early decelerations
Mixed decelerations
What kind of decelerations are a sign of foetal distress?
Late decelerations
What maternal measurements should you do in suspected foetal distress?
BP
HR
Where can you take blood from to determine if a foetus is hypoxic?
Scalp capillaries via vaginal exam
Umbilical cord on delivery
What are two tools used in assisted vaginal delivery?
Forceps
Ventouse suction
Say there is failure to progress in pregnancy (without epidural anaesthesia). How long would you try for a spontaneous vertex delivery before attempting assisted vaginal delivery in a
a) primagravida
b) multiparous woman?
a) 2 hours
b) 1 hour
What type of pain relief prolongs labour?
Epidural anaesthesia
Between forceps and Ventouse delivery, which is more successful?
Forceps
Suction cups tend to fall off
Which placental problems are more likely in subsequent Caesarean sections?
Placenta accreta
Placental abruption
What are the reversible causes of cardiac arrest?
FOUR Hs:
hypoxia, hypovolaemia, hyper/hypokalaemia, hypothermia
FOUR Ts:
tension pneumothorax, tamponade, thrombosis, toxins
Which type of drug should you consider using if uterine contractions are causing foetal distress in premature labour?
Tocolytic drugs
e.g terbutaline, they terminate contractions for up to 48h
What are the four Ts of reversible cardiac arrest?
Tension pneumothorax
Cardiac tamponade
Thrombosis
Toxins
What are the four Hs of reversible cardiac arrest?
Hypovolaemia
Hypoxia
Hyper/hypokalaemia
Hypothermia
Why may a pregnant woman become shocked if she is lying on her back?
Compression of aorta/IVC
If a pregnant woman needs CPR, immediate C section is often lifesaving because otherwise she can’t lie flat
