Normal Labour Flashcards
Define normal labour?
Spontaneous labour at term (37-42 weeks) with fetus in vertex position resulting in a Spontaneous Vaginal Birth (SVD)
What physiological changes must occur for labour to initiate? [3]
- Cervix softens
- Myometrial tone changes to allow for coordinated contractions
- Progesterone decreases while Oxytocin + Prostaglandins increase
There are 3 stages of labour
What are the parts of Stage
1 of labour? [2]
Latent first stage
Established first stage
What occurs during the latent first stage of labour?
Phase from full cervical dilation to birth of baby.
What occurs during the Established first stage of labour?
Duration in primi and multigravida? Rate?
Intermittent painful contractions leading to up to 4cm of dilatation
Regular Painful contraction producing progressive cervical effacement and 10cm dilatation.
Established first stage lasts an average 8 hours primagravida and 5 multigravida. Progresses at 0.5-1cm per hour
The second stage of labour has 2 stages:
What occurs in the Passive 2nd stage of labour?
NB Allow 1 hour for the fetus to descend
This is the stage after your fully dilated but before Involuntary Expulsive Contractions occur
What occurs in the Active Second stage of Labour? [3]
Expulsive contractions with full dilatation. The presenting part of fetus is visible and active maternal effort is required
How long does the Active second stage of labour take?
Average 2 hours for primagravida and 1 for multigravida
What occurs during the 3rd stage of labour?
Expulsion of the placenta and membranes
What are the different ways we can handle the 3rd stage of labour?
- Active Management
- Physiological management - only admissible to women who are low risk for PPH or placental delivery complications
Whats involved in Active management of the 3rd stage? [3]
What is prolonged third stage [2]
- Uterotonic drugs
- Deferred (2-5 mins) clamping and cutting of cord
- Delivery of placenta by controlled cord traction
Prolonged Third Stage is a diagnosis made after 30 minutes of active management or 60 minutes of physiological management
We use a partogram once established labour has been confirmed to monitor the labours progress. What tests/measurements would this include other than evaluating ‘external signs’ [6]
- Abdominal Palpation, palpate uterine contractions
- Vaginal Exam
- Monitoring colour, smell and volume of liquor
- Fetal Heart rate
- Vital signs: BP/Pulse/Temp/RR/O2Sat/Urine output/Urinalysis
What does abdominal palpation tell us about the labour? [6]
Fetal Lie Presentation Attitude Denominator Position Engagement
Define Fetal Lie and what are the 3 possibilities
Define Fetal Presentation [1]
Axis of foetus to mother. Either Longitudinal (same axis as mom) or transverse (lying sideways) or Oblique
The part of the foetus that is foremost in the birth canal
Define Fetal Attitude [1] and give examples [5]
Define fetal engagement
Foetus’s posture
i.e. back concave, straight or convex and head tilted forward or back
Degree to which the baby’s presenting part (head in vertex) has entered the pelvic inlet
Define Fetal Position
What is it determined by [1]
What are the 2 factors that influence it?
Orientation of the foetus. Determined by which way the occiput (post fontanelle) is facing.
1) anterior vs posterior vs transverse
2) and left vs right
What can be discerned on vaginal exam during labour? [3]
Fotal presentation, engagement & position
Cervical effacement and dilatation
Presence/absence of membranes
How do we auscultate the foetal heart? [3]
How often should be auscultate the foetal heart if doing it intermittently? [2]
Intermittently with hand held doppler or Pinard
OR Continuously with Cardiotocograph (CTG)
Every 15 minutes in first stage and every 5 minutes in 2nd stage
What do you look for when palpating uterine contractions? [2]
3-4 every 10 minutes lasting 40-60s each
Strength: moderate to strong not weak
What are some external signs of labour? [2]
Rhomboid of Michaelis
Anal Cleft line
What are the parts of the actual mechanism of labour? [7]
Descent Flexion (of head) Internal rotation of head (so facing downward) Crowning and extension of head Internal rotation of shoulders External rotation of head Lateral flexion to deliver shoulders
What forms of analgesia can women get during labour? [7]
- Breathing and massage
- TENS
- Paracetamol and Dihydrocodeine
- Entonox
- Epidural
- Remifentanil as Patient controlled Analgesia
What is entonox?
Inhalation Nitrous Oxide and oxygen
Aka gas and air
Partogram
What is its importance? [2]
Other information recorded down [6]
Records progress of cervical dilation and descent of head Enables recognition of a labour that is non-progressive - Frequency, duration of contractions - FHR - Colour of liquor - Caput and moulding - Station/descent of the head - Maternal heart rate, BP, temp
What are indicators of fetal hypoxia? [2]
Changes in fetal heart rate
Passage of new meconium-stained liquor
Indications for CTG NICE guidelines [5]
As per NICE guidelines; the following would warrant continuous CTG monitoring if any of the following are present or arise during labour;
- suspected chorioamnionitis or sepsis, or a temperature of 38°C or above
- severe hypertension 160/110 mmHg or above
- oxytocin use
- the presence of significant meconium
- fresh vaginal bleeding that develops in labour - this was a new point added to the guidelines in 2014
What are the 2 components of interpreting CTGs?
Basal heart rate
- FHR 110-160 bpm
Baseline variability
- Normally varies between 5-25bpm
What is baseline variability? [3]
Reduced variability causes [4]
What is a red flag level of variability?
- Baseline variability is a record of oscillations in heart rate around baseline
- Due to the millisecond-to-millisecond reactions of the sympathetic and parasympathetic activity on the heart
- Reflects integrity of the ANS
Reduced variability:
- Fetal sleep phase
- Hypoxia, infection and medication
<5 bpm variability = fetus in jeopardy
Transient changes in FHR
Accelerations - clinical significance [2]
Decelerations classified into [3]
Accelerations: reflection of activity of somatic nervous system > reassuring sign of good fetal health
Decelerations
- Early, late, variable
Early Decelerations of FHR
Pattern [3]
Ax
Timing
- Synchronous with uterine contractions
- Nadir occurs at peak of contraction
- Decrease in heart rate <40 bpm
Ax: head compression, considered physiological
Timing: seen in late first and second stage labour
Late Decelerations of FHR
Pattern [2]
Ax [2]
- Onset of slowing HR occurs well after contractions
- Doesn’t return to normal baseline until at least 20s after contraction completed
Ax: placental insufficiency, may indicate fetal hypoxia
What are methods of fetal monitoring? [4]
Intermittent auscultation
CTG
Fetal electrocardiogram
Fetal acid-base balance = Fetal scalp blood sampling
Fetal acid-base balance
Obtained from scalp through amnioscope
Position: left lateral to avoid risk of supine hypotension
Sample analysed in blood gas analyzer
