Labour Flashcards
Define labour
The process in which the fetus, placenta and membranes are expelled via the birth canal.
Results in a spontaneous vaginal birth (SVD).
What is considered term in pregnancy?
37-42 weeks
What key physiological changes must take place to allow for expulsion of the fetus?
- Cervix softens
- Myometrial tone changes to allow for coordinated contractions
- Progesterone decreases/Oxytocin and prostaglandins increase to allow initiation of labour
What does stage 1 of labour consist of?
- Latent first stage
- Established first stage
What takes place in the latent first stage of labour?
-Uterine contractions, starting at the fundus
When does the established first stage of labour begin?
Cervix dilated to 5cm
When does the established first stage of labour end?
Cervix fully dilated (10cm)
What does stage 2 of labour consist of?
Full cervical dilation to birth of baby
Passive and Active second stage
What does stage 3 of labour consist of?
Expulsion of placenta and membranes
What is involved in active management of third stage of labour?
Routine use of uterotonic drugs, optimal cord clamping, controlled cord traction (oxytocins)
What defines prolonged third stage of labour?
If third stage is not completed within 30 minutes of birth.
What is involved in progress and monitoring of labour?
- Maternal observations
- Abdominal palpation
- Vaginal examination
- Monitoring of liquor
- Auscultation of fetal heart
- Palpation of uterine muscle contractions
- External signs eg Rhomboid of Michaelis and cleft line
What is used to monitor fetal heartbeat?
CTG (Cardiotocography)
What are the different types of fetal lie in pregnancy?
- Oblique lie
- Longitudinal lie
- Transverse lie
What head position is easiest for birth?
Occiput anterior (OA)
What are the mechanisms of labour?
- Descent
- Flexion
- Internal rotation of the head
- Crowning and extension of head
- Restitution
- Internal rotation of shoulders
- External rotation of the head
- Lateral flexion
What defines crowning?
The widest part of the vertex coming out?
What analgesia are used in labour?
- Breathing, massage, TENS, paracetamol, dihydrocodeine,
- Water
- Entonox
- Opioids
- Remifentanil and patient controlled analegsia
- Epidural
- Maternal positioning
Approximately how many pregnancies are induced?
1 in 5
What risks may be involved in induction of labour?
Uterine ‘hyperstimulation’ with prostaglandin/oxytocin induction
List some indications for induction
Diabetes
Post dates - Term + 7 days
Maternal health problem that requires planning for delivery (eg DVT treatment)
Fetal reasons (growth concerns, oligohydraminos)
What is involved in induction?
- Instigation of labour artificially using medications/devices to ‘ripen cervix’
- Usually followed by artificial rupture of membranes
What scoring system is used to clinically assess the cervix in induction?
Bishop’s score
What can be used to ripen (open) the cervix?
Prostaglandin pessaries/Cook Balloon
What Bishop’s score is considered favourable for amniotomy?
7 or more
What is an amniotomy?
Artificial rupture of fetal membranes usually using a sharp device eg amniohook
What medication is used following amniotomy to achieve adequate contractions?
IV oxytocin
What factors are used to determine progress in labour?
Cervical effacement
Cervical dilatation
Descent of fetal head through maternal pelvis
What defines suboptimal progress in the active first stage of labour?
Cervical dilatation less than 0.5cm/hour in primigravid women/ 1cm/hour in parous women
What occurs in cephalopelvic disproportion (CPD)?
Fetal head is in the correct position for labour, but too large to negotiate maternal pelvis
Caput and moulding develop.
Give an example of malpresentation
Transverse position
What is malposition?
Fetal head is in incorrect position for labour, ‘relative’ CPD occurs.
Eg occipito-posterior and occipito-transverse
What is used to monitor fetal well being in labour?
Intermittent auscultation of the fetal heart
Cardiotocography
Fetal blood sampling
Fetal ECG
What is fetal heart rate?
110 - 160 bpm
What can indicate stress reactions in CTG?
Prolonged/Slow to recover decelerations
When is fetal blood sampling used?
-When abormal CTG occurs (provides a direct measurement of pH - likely hypoxaemia etc)
In which situations would you advise not to labour?
Obstruction to birth canal (major placenta praevia, masses)
Malpresentations (Transverse, shoulder, hand, ?breech?)
Medical conditions where labour would be unsafe
Specific previous labour complications
Fetal conditions
What percentage of births are assisted/instrumental deliveries?
15%
What types of instruments are used in instrumental deliveries?
Forceps
Vacuum extraction
What is an essential procedure for management of obstructed labour or fetal distress before cervix is fully dilated?
Caesarean section
What are the increased risks in caesarean section?
Increased risks of infection, bleeding, visceral injury and VTE.
What third stage complications can occur in pregnancy?
Retained placenta
Post partum haemorrhage
Tears (1st - 4th degree)
What are common problems in the post partum period?
Problems with infant feeding
Problems with bonding
Social issues
List some postnatal problems?
Post partum haemorrhage Venous throboembolism Sepsis Psychiatric disorders of the puerperium Pre-eclampsia
What defines primary postpartum haemorrhage?
Blood loss of >500ml within 24hrs of delivery
What defines secondary postpartum haemorrhage?
Blood loss of >500ml from 24hrs post partum to 6 wks
Why does pregnancy/post partum period increase the likelihood of DVT/PE?
-Hypercoagulable state
6-10 times more likely to develop DVT or PE
When do most eclamptic seizures take place?
In the postnatal period
When may synthetic oxytocin be used?
Induction of labour (IOL) and augmentation of labour
Roughly how long should birth take after active second stage of labour?
1-2 hours
(Depending on multigravida vs primagravida
Give some reasons for inadequate progress during labour
- Cephalopelvic disproportion (CPD)
- Malposition
- Malpresentation
- Inadequate uterine activity
- Other reasons for obstruction (cyst/fibroid)
Why is it important to exclude an obstructed labour in the circumstances of inducing labour in inadequate uterine activity?
Stimulation of an obstructed labour could result in a ruptured uterus
What risks are decrease in caesarean section?
Reduced risk of perineal injury compared to vaginal birth
What would be the role of the midwife during the post partum period?
- Continue to observe for signs of abnormal bleeding
- Observe for evidence of infection (Wound/Endometriosis/Breast)
- Debrief events around birth
Why is warfarin not used to treat DVT/PE in pregnancy?
Teratogenic
But can be used in breast feeding
When do most eclamptic seizures take place?
Postnatally
List some drug-free methods of reducing pain in pregnancy?
Birthing ball Birthing pools TENS machines Hypnotherapy Aromatherapy
What simple drugs are available for labour?
Entonox
Diamorphine
What advanced drugs are available during labour?
Remifentanil PCA (Patient Controlled analgesia) Epidural
What are some absolute contraindications to induction of labour?
Abnormal lie
Known pelvic obstruction such as tumour or large ovarian cyst
Placenta praevia
Fetal distress
What are some relative contraindications to induction of labour?
Previous caesarean section (Risk of rupture to scar tissue)
Asthma
When is augmentation of labour required?
When contractions reduce in frequency or strength in active labour, even after spontaneous onset.
What medication is used to augment labour, if indicated?
Oxytocin
What medications are used in the active management of the third stage of labour?
Syntometrine (Oxytocin and ergotamine)
Oxytocin
What medications are given if risk of preterm labour?
Steroids (Betamethasone/Dexamethasone) - improve fetal lung development
Tocolytics - inhibit uterine contractions
Which drugs are used in tocolysis?
Calcium channel blocker eg Nifedipine
Oxytocin receptor antagonist eg Atosiban
Beta2 agonists eg Salbutamol
Indomethacin
Acutely - Terbutaline/GTN
What is tocolysis
Inhibiting uterine contractions (sometimes to help prevent preterm labour)
What are some contraindications to epidural use in labour?
Thrombocytopenia, Coagulopathy Raised ICP Local sepsis Septic shock Allergy to local anaesthetic Recent anticoagulants
What is the general management of labour in multiple pregnancy?
-If first fetus is vertex presentation, normal delivery.
If both breech/breech-vertex - caesarean section
