Labour Flashcards
What is labour?
=Process of Delivery after 24/40; Onset is defined as point when Uterine Contractions become regular and Cervical Effacement and Dilatation becomes Progressive
o Show and ROM may or may not be associated with labour; Presence does not define
Braxton Hicks Contractions
Mild, Irregular, Non-progressive with may occur from 30/40; More common after 36/40; C/f Labour – Painful with gradual increments of Frequency, Amplitude and Duration
Normal Vertex Delivery
- Head enters pelvis in Occipitotransverse position; Increasing flexion of the head with descent
- Internal Rotation to Occipitoanterior occurs at the level of the Ischial Spines
- Crowning – Head extends and distends the perineum
- Restitution – Head rotates so Occiput is aligned with Foetal spine
- External Rotation, Delivery of Anterior and Posterior shoulder
First Stage of Labour
Divided into Latent Phase – Time taken for Cervix to completely Efface, plus Dilate to 3cm and
Active Phase – Dilatation from 3cm to completion (10cm)
Failure to progress
suspected if <2cm dilatation/4hrs (4hr Action Line on Partogram), or
Slowing in progress in parous women
Causes of failure to progress
Power =Inefficiency Uterine activity (Most common),
Passenger =Malpresentation, Malposition, Large baby, or Passage (Inadequate Pelvis)
Management of Failure to Progress
Review Maternal Hydration, Analgesia; Management options include Amniotomy,
Oxytocin Infusion (Especially in Primiparous women); Lower segment Caesarean
might be required if Foetal Distress
Monitoring In Labour
• FHR monitored every 15 minutes, or continuously with CTG; Contractions assessed every 30
minutes; Maternal HR every hour; BP and Temperature 4-hourly
• Vaginal Examinations offered every 4 hours to assess progress
• Maternal Urine tested 4-hourly or when passed – Ketones (DM) and
Protein (Pre-Eclampsia)
Second Stage of Labour
=Time between Full Cervical
Dilatation and Birth of Baby
Expulsion of baby
Expulsive efforts using abdominal muscles with Valsalva manoeuvre to bear down; Squatting, Standing, All-fours or Supine;
Lithotomy position for Instrumental Deliveries
What should be done when baby’s head is visible
Hand should be used to maintain Baby Head Flexion and prevent sudden Deflexion; Also, to
control rate of delivery (Slows down Perineal distention, Minimising tears)
o Episiotomy performed if concerns that Perineum is tearing towards Anal Sphincter; Should not be
performed routinely
What should be done after presentation of the head?
With next contraction, gentle
traction guides head towards Perineum until Anterior Shoulder delivered; Subsequent gentle traction supero-anteriorly to delivery Posterior
Shoulder and remainder of baby
Cord Clamping
Cord double-clamped and cut; Delayed cord clamping for 2-3 minutes results in higher Haematocrit levels in Neonate
What should be done once baby is delivered?
APGAR scoring, and if good progress, handed to mother as soon as possible
Delayed Second Stage
Suspected if not imminent after 1hr of active pushing; If Primiparous, Vaginal Exam and Amniotomy recommended (and if not delivery within 2hr for Obstetrician);
If Multiparous, for Obstetrician immediately; Suspect Malposition or Disproportion
Third Stage of Labour
Duration from Delivery of Baby to Delivery of Placenta and Membranes
Active Management of Third Stage
Uterotonics (Syntometrine, Oxytocin), Clamping and Cutting of cord, Controlled Cord Traction; Lower rates of PPH >1L, Blood loss and Anaemia, Duration and
reduced Transfusion requirements; SE: N+V, Headache
IM Syntometrine (Ergometrine 0.5mg, Oxytocin 5IU), or Oxytocin 10IU given as
Anterior Shoulder is born; Hand placed over Uterine Fundus with CCT (Brandt-
Andrew Technique)
Physiological Management of Third Stage
No Uterotonics; Cord allowed to stop pulsating before clamped and cut; Placenta delivered by maternal effort alone (No traction or Uterine manipulation)
o Convert to Active if Haemorrhage, Failure to delivery within 1hr, or patient request
Immediate post natal complications
Most complications occur in first 2h after delivery – PPH, Uterine Inversion, Haematoma
formation; Monitor Observations, Uterine Size and Contractions, PV bleeding or painful
welling of Genitourinary Tract
Prophylaxis of PPH with Oxytocin Infusion (40IU in 500ml NaCl) if high risk e.g. Multiple preg,
given for 3-4hrs
What should be done immediately
Skin-to-skin contact as soon as possible; Mother and baby should not be separated first hour;
Breast feeding should be initiated within first hour
• Transfer to Post-natal ward if no complications; Home after further 3 – 4hrs observation
Foetal surveillance in labour
Blood supply to Placenta is restricted due to Uterine contractions, especially in the second stage, placing
physiological strain on foetus during labour; Dependent on Foetal Reserve
• Intermittent Auscultation, or Continuous Cardiotocography (CTG,
also =EFM)
• If no risk factors, IA performed for a minute after contraction; At least
every 15 minutes in first stage, and every 5min, or after every other
contraction in second
Interpretation of CTG: Baseline Rate
– Mean FHR when
stable, after excluding Accelerations and Decelerations
o Bradycardia (<110bpm); <100 should raise possibility of Hypoxia
o Tachycardia (>160bpm); Associated with Maternal Pyrexia and Tachycardia,
Prematurity, Foetal Acidosis
Interpretation of CTG: Baseline variability
– Bandwidth after exclusion of Accelerations and Decelerations
o Decreased Variability can occur in Foetal Hypoxia, Foetal Sleep (Usually <40 mins, max 90 mins), Malformation or Arrhythmias, Drugs (Methyldopa, MgSul, Narcotic Analgesia, Tranquilisers, Barbiturates, GA), Severe Prematurity
Interpretation of CTG: Acceleration
Transient rise in FHR >15bpm lasting 15s or more
o Presence is normal but absence in otherwise normal is of uncertain significance
Interpretation of CTG: Deceleration
Reduction in FHR >15bpm lasting 15s or more o Early Decelerations – Peak of Deceleration Coincides with Peak of Contraction; Related to Head compression and seen in active second-stage o Late Decelerations – 15s lag between peak of Contraction and nadir of Deceleration; Might be suggestive of Acidosis especially if accompanied with Tachycardia and reduced Baseline Variability
Interpretation of CTG: Variable decelerations
Variable pattern of Timing, Size and Shape, associated with Cord Compression;
Typically, U or V shaped, quick to drop and recover; Not usually associated
with Hypoxia; Atypical features such as >60s, >60bpm dips, slow recovery
Interpretation of CTG: Sinusoidal Pattern
Rare undulating pattern with little to no variability; Can indicate significant foetal anaemia, or foetal behaviour (thumb-sucking)
o Blood group antibodies, Kleihauer test, MCA velocity scan to detect foetal anaemia
Foetal blood sampling
• Improve specificity of CTG to detect Foetal Hypoxia; Should be obtained if Pathological trace
unless obvious immediate delivery required
• Normal if pH >7.25; Borderline if 7.21 – 7.25; Immediate Delivery if ≤7.20
Meconium
Meconium comprises Water, Bile pigments, Mucous and Amniotic Fluid Debris;
Meconium-
Stained Amniotic fluid (MSAF)
assoc with Perinatal Morbidity/Mortality; May be Aspirated
o Incidence increases gradually from 36 – 42/40; Hypoxia can cause peristalsis of GI
tract and relaxation of Anal sphincters leading to MSAF
o Induction if ROM before labour; Continuous Foetal Monitoring, Foetal Blood
Sampling and Neonatal Life Support on standby
▪ Close monitoring 12h if born in good condition
Meconium Aspiration Syndrome
0.1% of births; Can happen In-utero, believed to be
associated with Prolonged Decelerations that cause Transient Hypoxia
o Mechanical Blockage, Chemical Irritation (Pneumonitis, Alveolar collapse), Predisposes to secondary bacterial infection
o Suction of mouth and upper airway not recommended if active baby crying; If Respiratory difficulty, should be cleared ± Laryngoscopy
