Obstetrics (Intrapartum care): Normal pregnancy + IOL Flashcards
What is the definition of stage 1 of labour?
Explain the features
Onset of labour to full dilatation (10cm)
- Involves decent, flexion, internal rotation
- membranes usually rupture
- Primigravida dilates at 1cm/hr - takes 8hrs (delay < 2cm in 4hrs)
- Multigravida dilates at 2cm/hr - takes 5hrs (delay < 2cm in 4hrs or slowing in progress)
What is the definition of stage 2 of labour?
Explain the features (i.e. difference between passive and active)
Full dilatation to birth of baby
a. Passive
- delivery with no expulsive contractions
- takes a few mins
b. Active
- delivery with expulsive contractions and maternal effort
- other features: anal dilatation, bulging perineum, red congestion mark
Nuliparous - usually 40 mins
Multiparous - usually 20 mins
if delay > 1hr, unlike to have normal vaginal delivery
Delivery
- head extends (crowns) and perineum stretches (can tear)
- if slow may have IUGR
- head rotates 90 degrees to transverse position
- shoulders delivered
What is the definition of stage 3 of labour?
Explain the features (i.e. difference between physiological and active)
From birth of baby to delivery of placenta and membranes
a. Physiology
- no uterotonic drugs or clamping cord (until pulsations stop)
- delivery of placenta by maternal effort (placenta separates from wall + uterus contracts down to prevent haemorrhage, normal blood loss 500ml)
b. Active
- Uterotonic drugs such as IM syntometrine (oxytocin)
- Delayed cord clamping and cutting of cord (until baby’s circulation is independent of mothers)
- Controlled cord traction
- Decreases risk of haemorrhage and shortens 3rd stage
What is the average duration of stage 1 labour for primigravida and multigravida women?
How do you know if its delayed?
5 hours - multigravida (delay if <2cm in 4hrs or slowing in progression)
8 hours - primigravida (delay if <2cm in 4 hrs)
What are the features of active stage 2 of labour?
Maternal effort
Expulsive contractions
Bulging perineum, Anal dilatation, Red congestion mark
What is the average duration of stage 2 labour for primigravida and multigravida women?
How do you know if its delayed?
20 mins - multigravida
40 mins - primigravida
Delay if > 1hr - normal vaginal delivery is therefore unlikely
what is normal blood loss during physiological 3rd stage of labour?
500 ml
Which cell creates foetal lung surfactant and at what age? What is its function
24 weeks - T2 pneumocytes create foetal lung surfactant stimulated by foetal gluco-corticoid and thyroid hormones.
Lung surfactant - decreases surface tension at liquid/air interface
Does the mother or foetus blood have a high O2 conc?
Foetal - higher concentration of oxygen due to foetal Hb (HbF) has higher concentration and affinity
What is the monitoring offered to low risk pregnancy?
Intermittent monitoring of foetal HR using a Pinard Stethescope (Sonicaid) or Doppler USS
- Monitor for 1 minute after every contraction
- Interval of 15 minutes
- record any accelerations or decelerations
How is a high risk pregnancy detected?
- Maternal uterine artery doppler
- 23 weeks
- uterine.a pressure is normally low resistance
- increased resistance indicates pre-eclampsia, placental abruption or IUGR - Blood test
- B-HCG and AFP measured
- Raised AFP indicates neural tube defect and increased risk for pregnancy
How does the baby move through the uterus from start to finish? (manoeuvres)
Don’t Forget I Eat Rhubarb In Labour
Descent Flexion Internal rotation of head Extension of head Restitution Internal rotation of shoulder Lateral flexion
Name some of the indications for high risk monitoring?
POP HAMM CSF
Prolonged stage 1 or 2 of labour Evidence of Use of Oxytocin
Prolonged period since rupture of membranes > 24hrs
Hypertension > 160/110
Abnormal intermittent foetal monitoring
Meconium stained liquor or bleeding
Multiple pregnancy or IUGR
Chorioamnionitis, Sepsis or Fever > 38
What are the features of a normal CTG?
Baseline Rate: 100-160bpm (usually ~ 130bpm)
Assess Variance: ≥ 5
Accelerations: present (not necessarily bad if absent)
Decelerations: none or early
What are the features of a non-reassuring CTG?
Baseline Rate: 161-180
Assess Variance: < 5 for 30-90mins
Accelerations: present or absent
Decelerations: Variable (>60bpm for <30mins) or Late (>60bpm for <30mins for >50% contractions)
What are the features of abnormal CTG?
Baseline rate: > 180 (tachycardia) or < 100 (bradycardia)
Assess Variance: < 5 for > 90mins
Accelerations: present or absent
Decelerations: Non-reassuring decelerations or Late (>60bpm for >30mins for >50% contractions)
What is the definition of normal, non-reassuring and abnormal CTG?
Normal = all four features are normal
Suspicious (non-reassuring) = one feature is classed as non-reassuring, remaining are normal
Pathological (abnormal) = two or more features are classed as non-reassuring or one or more features classed as abnormal
What are the actions you can take if you are worried about foetal wellbeing following?
- Move maternal position - mobilise or lateral position
- Give fluids and oxygen (if required)
- Paracetamol (if pyrexic)
- Foetal scalp stimulation - may cause accelerations :)
- Reduce contraction frequency by stopping oxytocin infusion - give tocolytic agent (e.g. Terbutaline 0.25mg
- Foetal blood sample - pH
- Delivery
What two features are monitored on foetal blood sample?
What are the requirements to do this?
What will you do for a normal, borderline and abnormal score?
pH and Lactate - invasive procedure of sampling blood, requires >3cm dilated
- pH
- normal ≥ 7.25
- borderline 7.21-7.24
- abnormal < 7.2 - Lactate
- normal ≤ 4.1
- borderline 4.2-4.8
- abnormal ≥ 4.9
- Abnormal - inform obstetrics and aim to expedite birth
- Borderline - repeat sample in 30 mins
- Normal - repeat sample in 1 hour
What other tests can be used to determine foetal health and wellbeing? not necessarily during labour (4)
- Foetal USS
- measure head and abdo circumference
- determine features of healthy growth
- i.e. measure rate of growth (compare scans 2 weeks apart), compare actual growth against expected growth, foetal abdo should stop growing before head - Doppler waveform of umbilical.a
- measure pressure - should have little resistance
- increased resistance suggests IUGR, placental abruption or pre-eclampsia - Doppler of foetal waveform
- measure MCA and ductus venous
- foetal compromise = low MCA resistance compared to thoracic aorta or renal vessels - USS of foetal biophysical characteristics
- measure arm and breathing movements, tone and liquor volume
- each scores 2, max 8 (10 if measured on CTG)
- Low score = high risk foetal compromise
- Low liquor volume = high risk of foetal distress during labour
What are the types of pain during stage 1 labour
Visceral pain - poorly localised + colicky
Uterine contractions (T10-L1)
Due to dilatation and pressure on pelvic organs (L1-S1)
What are the types of pain during stage 2 labour?
Sharp stabbing - well localised pain
Due to stretching of uterus and pressure on pelvic organs and floor structures
Via Pudendal nerve + Perineal (S2, 3, 4)
What are the non-pharmacological and pharmacological options for pain during labour?
Non-pharmacological
1. Acupuncture - do not offer, but do not stop if already started
- TENS (transcutaneous electrical nerve stimulation) - do not offer if in established labour
- Hydrotherapy - labour in water 37^o, must monitor temp hourly
Pharmacological
- Entonox - NO/O2
- quick onset + offset
- SE - amnesia, light headed, dizzy, nausea - Opioids - pethidine, morphine, MST, diamorphine
- SE mother - nausea, vomiting, constipated, respiratory depression
- SE baby - short term resp depression, drowsy (may last weeks)
What is the difference between a spinal and epidural block?
- Epidural
- Injection of LA ± opioid into epidural space at L3/4
- Administered via epidural catheter
- Bupivicane and Fentanyl used to induce
- Provides complete sensory (except pressure) and partial motor block from upper abdomen downward
- requires CTG monitoring for 30 mins post admin during establishment of analgesia + for every further 10mls injected - Spinal
- Injection of LA into subarachnoid space into CSF
- L3/L4
- preferred analgesia for CS (if epidural not already in place)
- More dense block
