Obstetrics: Labour, Delivery and the Puerperium Flashcards
How is labour defined?
Progressive effacement and dilatation of the cervix in the presence of regular uterine contractions.
Define delivery?
Expulsion of the foetus and the placenta
What is SRM?
Spontaneous rupture of membranes, can precede labour
What is ARM?
Artificial rupture of membranes
What is Gravidity?
Total number of pregnancies including present.
What is Parity?
The state of having given birth.
How long does labour normally take for a nulliparous and multiparous woman?
NP = 2-14 hours MP = 1-11 hours
What factors influence the speed of Labour?
The passage:
- The pelvis, size of inlet and outlet
- The soft tissues (lower uterine segment, cervix, vagina, vulva, pelvic floor, perineum)
The powers:
- Contractions (speed and frequency)
The passenger:
- Lie
- Presentation
- Denominator
- Position
- Foetal head shape/circumference resulting from varying degrees of flexion
Describe the stages in the mechanism of labour?
1) Engagement
2) Flexion
3) Descent
4) Internal Rotation
5) Extension
6) External Rotation
At what rate do you expect contractions to occur?
Early Labour = every 3-4 minutes
Advanced Labour = every 2-3 minutes
What is the foetal lie?
The relationship between the long axis of the baby and that of the mother (long, oblique, transverse)
What is the foetal presentation?
The part of the foetus lowermost in the uterus e.g.
- Cephalic
- Vertex
- Brow
- Face
- Breech
- Shoulder
What is the foetal denominator?
Part of foetus used as reference point to describe position in maternal pelvis (occiput, mentum, sacrum, acromion)
What is the foetal position?
Relation of the foetal denominator to the maternal pelvis (occipitoanterior, occipitotransverse, occipitoposterior)
What maternal monitoring is required during labour?
- Obs
- Hydration
- Analgesia
- Antacids
- Bladder care
- Position
- Progress (contractions, cervical dilatation, descent of presenting part)
- Perineum
- In 3rd stage of labour: active management, Oxytocics, controlled cord traction
What are Oxytocics?
Medications such as…
- Oxytocin (Pitocin)
- Methylergonovine (Methergine)
used to…
- Induce labour
- Treat labour arrest
- Active management of labour
- Treat uterine atony and post-partum haemorrhage
What is Controlled Cord Traction?
Controlled cord traction (CCT) is traction applied to the umbilical cord once the woman’s uterus has contracted after the birth of her baby, and her placenta is felt to have separated from the uterine wall, whilst counter-pressure is applied to her uterus beneath her pubic bone until her placenta delivers
What foetal monitoring is required during labour?
- Foetal heart monitoring
- Colour of Liquor
What are Braxton Hicks contractions?
Painful, practice contractions that occur from the first trimester but most commonly from the 36th week. About 1/4th as strong as regular contractions.
When is Labour considered normal?
- After 37 weeks
- Resulting in spontaneous vaginal delivery of the baby within 24 hours of the onset of regular spontaneous contractions
- Often preceded by a ‘show’ a plug of cervical mucus and a little blood as the membranes strip from the os
What happens in the first stage of Labour?
Latent phase:
- Painful irregular contractions
- Cervix initially effaces (gets shorter and softer
- Then dilates to 4cm
Established phase:
- Regular contractions
- Further dilation at a rate of about 0.5cm/hour, up to about 10cm
Takes 8-18 hours in a primip, 5-12 hours in a multip
What monitoring is required during the first stage of Labour?
- Maternal BP, Temp every 4 hours. Also offer vaginal exam to look at dilation and foetal head position
- Pulse every hour
- Strength and frequency of contractions every half hour
- Auscultate foetal hart rate every 15 mins
Note liquor colour and frequency of bladder emptying.
What happens in the second stage of labour?
Passive stage:
- Complete cervical dilation
- No pushing
- Ideally should last 1-2 hours
Active stage:
- Mother uses abdominal muscles and valsalva maoeuvre until baby is born
- Head descends, perineum stretches, anus gapes
- Expect birth within 3 hours NP, 2 MP.
- Refer if not imminent at 2/1 hours.
- Can give oxytocin if contractions waver at this stage
What monitoring is required during the second stage of Labour?
- Temp 4 hourly
- BP and pulse hourly
- Assess contractions half hourly
- Auscultate for heartbeat every 5 mins (for 1 minute)
- ## Record urination during second stage
How long do you wait after birth before clamping the cord?
1 min in healthy babies, 3 mins in premature babies (reduces risk of anaemia).
What is involved in the third stage of labour?
Delivery of the placenta:
- Uterus contracts
- Placenta separates
- Buckles and a small about of retroplacental haemorrhage occurs.
Normally takes an hour.
How can the third stage of labour be reduced?
Delivery of Syntometrine (combination of oxytocin and ergometrine maleate) reducesd third stage to 5 minutes and decreases the incidence of PPH.
CIs: Pre-eclampsia, Severe HTN, Liver or Renal impairment, Severe heart disease
What are the most common problems which occur in labour?
- Failure to progress (a delay in the first or second stage)
- Malpresentation /Malposition
- Suspected Foetal Compromise (foetal distress)
- VBAC (Vaginal deliver after birth) complications
- Operative Delivery
- Shoulder Dystocia
What are the issues with breech presentation?
- Increased perinatal morbidity and mortality
- Higher incidence of foetal abnormality and neuro-developmental problems regardless of mode of delivery
- Complications at delivery: head can become trapped, cord can prolapse, intracranial haemorrhage..
What are the delivery options for a breech presentation baby?
- External Cephalic Version (a manoeuvre where the baby is flipped around while still in the uterus)
- Elective Caesarean Section
- Vaginal breech delivery (risk)
What is a CTG?
Cardiotocography (CTG) is used during pregnancy to monitor fetal heart rate and uterine contractions.
What features on a CTG could indicate suspected foetal compromise
- Baseline tachycardia or bradycardia
- Reduced baseline variability
- Absence of acceleration (non-reactive)
- Presence of decelerations
What test needs to be performed if suspected foetal compromise on CTG and why?
CTG has high sensitivity and low specificity, so need to confirm something is really wrong with…
Fetal Acid-Base Status (following fetal scalp blood sampling)
If unable to do FBS deliver by speediest route.
What are some causes of foetal compromise during labour?
- Uterine hyperstimulation
- Hypotension
- Poor foetal tolerance of labour (e.g. if IUGR)
- Cord compression
- Infection
- Maternal disease
How should confirmed foetal compromise be managed?
- Look for and treat any reversible causes (e.g. maternal hypotension)
- Put mother in LLP
- Stop oxytocics
- Confirm compromise by blood sampling
- If possible deliver by speediest route if unable to correct or if significant acidosis
What is VBAC and what risks are associated with it?
When a woman who has previously had a C section goes on to have a vaginal birth.
Risks:
- Emergency need for a C section
- Uterine scar dehiscence or rupture
What precautions should be taken for a mother going for VBAC?
- IV access and G+S
- Continuous electronic foetal monitoring
- Avoid prolonged labour
- Augmentation or induction should only be senior decision
What are the indications for an operative delivery?
- Failure to progress in stage 2 of labour
- Foetal distress in 2nd stage
- Maternal reasons.
What are the prerequisites for operative delivery?
- Full dilatation
- Absent membranes
- Cephalic presentation
- Clearly defined presentation
- Presenting part engaged
- No evidence of CPD
- Adequate analgesia
- Empty bladder
What are the possible complications of operative delivery?
- Failure
- Fetal trauma
- Cephalhaematoma
- Maternal trauma
- Postpartum haemorrhage
- Urinary retention
What are the indications for C section?
- Failure to progress
- Fetal distress due to maternal reasons
- Malpresentation or malposition
- Failed instrumental delivery
What are the possible complications from C section?
- Haemorrhage
- Infection
- Bladder/bowel injury
- Thromboembolic disease
- Requirement for blood transfusion
- Transient Tachypnoea of the New-born
- Trauma to the foetus
What is shoulder dystocia?
Inability to deliver shoulders after delivery of head as anterior shoulder does not enter pelvic inlet
What are the risks of shoulder dystocia?
- Foetal death
- Asphyxia with resulting hypoxic damage (e.g. brain)
- Birth trauma e.g. Erb’s palsy, fractured bones
What babies are most at risk of shoulder dystocia?
- Macrosomic foetus
- Foetus of diabetic mother
- Rotational instrumental delivery
What obstetric manoeuvres can be used to manage shoulder dystocia risk?
- The McRoberts position (flexion and abduction of the maternal hips, positioning the maternal thighs on her abdomen)
- Suprapubic pressure
What are the main causes of delay in labour?
- Power (inadequate contractions)
- Passenger (malpresentation or malposition of the foetus)
- Passage (inadequate pelvis)
In all likelihood it’s a combination of the three
How is ‘normal’ labour progression conceptualised?
Cervix dilation of roughly 2cm per 4 hours of active labour.
Other factors should be bared in mind (e.g. descent of the head and effacement of the cervix) and assessment should be made dynamically throughout.
Define a delay in the 1st stage of labour?
Less than 2cm dilation in 4h in any women, or slowing progress in 2nd/3rd/4th… labours.
What assessments do you make if you observe a delay in the first stage of labour?
- Assess woman, review notes and obstetric history
- Palpate her abdomen for lie, palpable head, contractions
- Check foetal heart rate
- Colour of amniotic fluid
- Vaginal assessment; dilatation, effacement, caput, moulding, station of the head, position
- Does the mother need analgesia and rehydration
How would you manage a delay in the first stage of labour?
- Offer ARM, reassess in 2 hours
- Empty bladder as this can prevent descent of the head + reduce frequency of contractions
- If membranes are already ruptured; Oxytocin infusion, reassess after 4 hours (often takes 8 to work)
- Start continuous foetal heart rate monitoring with Oxytocin
- Consult senior if multiparous or previous C section, as increased risks related to rupture.
- Consider epidural and put mother in LLP
- If progress remains slow consider C section
Define a delay in the 2nd stage of labour?
No birth after 2 hours of active pushing for a primip or 1 for a multip.
Reasons are the same but also add maternal exhaustion.