Labour Flashcards
What are the four characteristics of labour?
Uterine contractions Cervical dilatation and engagement Rupture or membrane Descent of presenting part Birth of baby Delivery of baby
What dilation is the cervix in stage 1 of labour?
What position is baby’s head?
How quickly does the head progress?
4-10cm
Occipitotransverse with increasing flexsion
0.5 cm per hour
How can head position be described in stage one
- In relation to Ischial spine
2. Palpable above public bone
What are the 3 stages of stage 2 of labour?
Passive: full dilation of cervix prior to urge to bear down. Rotation and flexion complete. Only a few mins.
Active: explosive contractions with active maternal pressure. As head is visible only encourage small pushes.
Delivery:
Head extendeds and restitutes to transverse position. Delivery of shoulder (anterior first). If slow can cause feral distress.
What pneumonic can be used to remember the descent of the baby in labour?
Don’t forget I eat rhubarb in labour
Descent Flexion Internal rotation Extension of the head Restitution Internal rotation of shoulders Lateral flexion
What are the 3 mechanical factors of labour? Think the 3 ps
The powers: the uterus contracts, effacement of cervix
The passage: shape of bony pelvis and cervical dilation
The passenger: size of head, rotation of head, extension/flexion
How often does the uterus contract in labour?
45-60 seconds every 2-3 mins
What is effacement?
Difference between primos and multiple
When the cervix effaces, a mucus plug passes out of the vagina “bloody show”
Primips: external os remains closed until effacement is complete
Multiple: occur simultaneously
What is the longest diameter of the bony pelvis at the inlet and at the outlet?
Inlet: transverse
Outlet: AP
Hence why the head rotates during the descent
Cervical dilatation is dependant on what?
Contractions
Fetal head pressure on cervix
Ability of cervix to soften
With maximum flexion how long is the presentation?
What is it a brow presentation (90 degrees)
What if it’s face presentation (30 degrees)
Norma: 9.5 cm
Brows: 13cm
Face: may be too big to deliver
How much should the head rotates during labour?
What percent are OA? What happens if the baby’s head doesn’t rotate OT?
90 degrees .
90% OA (5% OP - more difficult birth)
Occipitotransverse- require forceps
What can you say under each of these headings when describing the fetal head
Presentation: Part in Lower pelvis, cephalic or breech Presenting part: Lowest part palpable on vaginal examination Cephalopod: vertex, brow, face Position: OA, OP, OT Attitude Describes degree of flexion
What can be the causes of damage to the fetus?
Fetal hypoxia Infection/inflammation in labour Meconium aspiration Trauma Fetal blood loss
If the amniotic fluid is brown, what does this suggest?
What affects could this have?
What precautions would you take?
Meconium in a. Fluid.
Increases perinatal mortality by 4 X as baby may aspirate it (chemical pneumonitis) and become hypoxia
In low risk pregnancies, not requiring CTG, how often and how do you monitor FHR?
Pinards stethoscope or hand held Doppler
- every 15 mins in stage 1
- every 5 in 2nd
What are the normal and abnormal values for fetal blood sampling? What is pH indicative of?
pH above 7.25 is normal
7.2-7.25 is borderline
Below 7.2 is v bad deliver baby
Sign of hypoxaemia
What is the pneumonic for CTG interpretation?
DR C Bravado
Determine risk Contractions baseline rate Accelerations Variability Decelerations Overall impression
What are high risk pregnancies that require CTG?
Meconium stained liquor Multiple pregnancies IUGR Oxytocin infusion Abnormality on intermittent auscultation
If there were over 5 contractions in 10 mins?
What is not measured by contractions
Hyperstimulation
Not intensity
What is the normal baseline rate?
High is associated with …
Low is associated with….
110-160
High: fever, infection
Low: hypoxia
What is variability a flexion of? After how long would you be worried the baby is not sleeping?
Reflection of autonomic NS, often first thing to become abnormal on CTG.
After 45 mins below 5bpm
What type of decelerations are worrying?
Late: fetal hypoxia - have to have morphology
Variable
Atypical: over 60s and over 60bmp
Sign of mechanical or hypoxia stress
Is CTG was non-reassuring or abnormal what could you do?
Change maternal position: L lateral Give fluids & oxygen Stop oxytocin infusion Fetal blood sample Delivery
How many women are asymptomatic with group b strep infection.
What effect can this have if mother is infected during labour?
Early onset group B streptococcus (GBS) infection.
At term = 6% mortality
What is Tx for group B strep? Is here screening in UK? Who is treated?
No screening in U.K.
TX high risk - precious affected neonate / +ve urinary culture Preterm labour Rupee of membrane over 18 hr Maternal fever in labour
What form is used to making monitor maternal progress? What factors does it record?
The partogram Patient demographics and risk Maternal observations (every 30min) Contractions Cervical dilation (PV every 4 hours)- look at trend and response to oxytocinin Head descent Liquor Final birth details
What is the apgar score? What does it measure? When would you require paediatric support?
Babe score 1-5 mins after birth to determine well being.
Records:
Appearance, pulse, grimacing, activity and respiration from score 0, score 1 or score 3
If total score is under 7 need paed support and oxygen
Side effects of Entnox
Feeling faint, N&V, hyperventilation
What mild analgesic can you not give? Why?
NSAIDS- premature closure of ductus arteriosis
What opioids are given in labour? Ads and dials?
Pethidine, meptid IM or IV
Ads: easily administered PCS
Disads: sedation, confusion, antiemetic needed, can cause respiratory distress of new born. Not complete analgesia
What are the side effects of spinal anaesthetic?
Hypotension, total spinal analgesia and RA
When & where can you insert a epidural?
Once labour is established between L3 & L4.
What are the advantages of epidural?
Pain free Advised in prolonged labour ↓ BP in hypertensive women Abolish premature urge to push Analgesia for instrumental delivery or CS
Disadvantages for epidural?
Hypotension Local anaesthetic toxicity ↑ instrumental delivery rate Bed bound: pressure sores Urinary retention require catheter maternal fever spinal tap 'headache'
Contraindications for epidural?
Patient refusal
Anti-anticoagulation & bleeding disorders
Local or severe infection
anaphylaxis to LA
Complications of epidural?
Immediate: Failure, hypotension, LA toxicity, total spinal
Delayed: postpartum puncture headache, infection, haematoma, neurological damage
What are the indications for induction of labour?
Risk of continuing pregnancy > achieving a vaginal birth.
Obstetric Indications: Uteroplacental insufficiency IUGR Prolonged pregnancy (41-42 weeks) Oligo- or anhydraminos Abnormal CTG PROM Severe PET IUD Antepartum haemorrhage
Medical Indications:
With underlying medical conditions, planned induction of labour may limit the maternal risks associated with pregnancy.
Severe hypertension + PTE
Uncontrolled hypertension
Renal disease with deteriorating renal function
Malignancies
What are the absolute and relative contraindications for induction of labour?
Absolute: Acute fetal compromise Abnormal lie Placenta praaevia Pelvic obstruction (pelvic mass, deformity)
Relative:
1 previous LSCS (↑scar rupture rate)
Prematurity
High parity
What is the bishop score?
A scoring system to predict the likelihood off successful induction.
A higher score indicates the cervix is more favourable
What does it measure?
Position, consistency, effacement, dilation and station.
What modifiers add one point?
PTE and previous VD
What modifiers subtract a point?
Postdate pregnancy, nulliparity, PPROM (premature rupture of membrane)
After ARM using amniohook induction, what percentage of women will go straight into labour?
80%
For how long do you wait in primps and multis before starting the oxytocin infusion
Primip: 2 hours
Multip: 4 hours
What are the complications of ARM
- inefficient uterine activity
- instrumental delivery/LSCC
- Hyperstimulation of uterus
- PPH
- Infection
Methods for cervical ripening
stretch & sweep
Prostgladins
Oxytocin infusion
What bishops score would indicate the need for cervical ripening?
< 5
How long after prostaglandins should you wait before giving oxytocin? why
6 hours, hyper stimulation
What is augmentation
using prostaglandins or oxytocin once labour is established
What is malposition? What are the 3 categories
Lie of foetus not parallel to axis of uterus
- longitudinal
- Oblique
- Transverse
How common
1 in 200
What are the causes
Preterm labour
Circumstances that allow more room to turn:
Polyhdramnios
Multiparity
Conditions that prevent turning:
Placenta praaevia
Pelvic mass
Conditions that prevent turning:
Fetal or uterine abnormality
Twins
NB: ‘unstable’ or continually changing lie in nulliparous women is rare.
Management
< 37 nothing
CS is almost always indicated do USS to identify cause.
Malpresentation (breech)- what is it? classifications?
Part of fetes that occupies lower segment
- extended (70%)
- flexed
- footling
what is the most common cause?
Preterm labour (25%)
management plan for breech
ECV @ 36 week (primi), 37 (multip)
Vaginal delivery or Elective LSCS.
Vaginal birth more dangerous
What factors increase the risk of vaginal birth?
baby >4kg, extended head, footling leg
Clinical features of multiple pregnancies
Hyperemesis gravidarum
Uterus larger than for expected dates
3+ poles felt by >24 weeks
2 fetal heart sounds on auscultation
Many diagnosed by USS in 1st trimester; dating or nuchal translucency scan.
Determine chronicity: 1st/2nd trimester USS
Dichorionic: widely separates, ‘Lamda’ sign, dividing membrane, different sex
- Monochorionic: T sign, dividing < 2mm
Which twins are at risk of twin to twin transfusion syndrome?
Monochorionicity twins
How many times more likely is a multiple pregnancy to have pre-eclampsia than a singleton?
5 times
Discuss the management of labour in a multiple pregnancy.
Vaginal delivery can occur if the first fetus is cephalic (regardless of second twin). CS is preferred, as is indicated for triplets +.
Induction or CS occurs ar
37-38 weeks for DC twins
34-37 weeks for MC twins
Labour:
- Conintous CTG
- 2 paeds staff, anaesthetic and 2 midwives
- Oxytocin after 1st baby
- ECV if second baby has abnormal lie
- If any distress -> forceps/ventouse.
What are the 3 types of forceps - when are they used
- ventouse: most deliveries
- Non-rotational forceps (simpsons & neville barnes): only if OA: has pelvic and cephalic curve
- Rotational: Keillands: allow rotation by operator no pelvic curse
Can be used if second stage of labour need to be expedited.
Indications for forceps
Prolonged second stage 1hr of pushing (active 2nd stage) Mother is exhausted Fetal distress in second stage When maternal pushing is contraindicated Cardiac disease Hypertension Breech delivery
What indications should be met before using forceps
- Cervix is dilated
- Position of head is known
- head must not be palpable abdominally
- Head below ischial spines
- Adequate analgesia
- Bladder empty
- valid indication
Indications
Failure: more commonly ventouse (cup misplaced)
Maternal trauma: lacerations, haemorrhage, third-degree tears, ↑ analgesia
Fetal trauma: lacerations, bruising, facial nerve injury, hypoxia if prolonged delivery, ‘chignon’: swelling in scalp. Ventouse = worse.
What are the rates OF CS
20-30%
Elective reasons for CS. When is performed
39 weeks Breech presentation Prv LSCS Placenta praevia Realtive: severe IUGR, twins, DM + other medical disease, prv LSCS <34 weeks: severe PTE, severe IUGR
Emergency reasons for CS
Emergency: Failure to advance full dilatation not occurred by 12hr Indications for instrumental delivery not met Often due to inefficient uterine action Fetal distress FHR & fetal blood sampling
Complications
Material:
- Haemorrhage
- Blood transfusion
- Uterine/wound sepsis
- VTE
- Risk of anaesthetic
- Subsequent pregnancies (p. praevia & accreta)
Fetal:
Fetal resp morbidity
Bonding & breastfeeding
How common is shoulder dystocia
1 in 200
Complications of shoulder dystocia
Erb’s Palsy
Delay in delivery- can be lethal
Risk factors for should dystocia
Large baby Previous shoulder dystocia ↑ BMI Labour induction Low height Maternal DM Instrumental delivery
Management
Senior help
McRoebrt’s Maneovre + suprapubic pressure (works in 90%)
Cord prolapse can cause what to the fetus?
Ischaemic enchepalopathy
Diagnosis
increased FHR and cord palpated vaginally
What can present with anaphylaxis, sudden dyspnoea, hypoxia Can lead to seizure & cardiac arrest or acute heart failure
Amniotic fluid embolism
What are the consequences if the mother survives over 30 mins
DIC
Pulmonary oedema
ARDs
When can amniotic fluid embolisms occur
Membrane rupture
Labour
CS
termination of pregnancy
What the two main complications of uterine rupture?
- acute fetal hypoxia
- massive internal haemorrhage
Clinical features of uterine rupture
Abnormal FHR Constant lower abdominal pain Tenderness over scar Vaginal bleeding cessation of contractions maternal collapse
Risk factors
labours with a scarred uterus - classical CS - deep myomectomy - LSCS (lowest) Neglected obstructed labour Congenital uterine abnormality Previous rupture (high recurrence rates)
Prevention
avoid induction
caution when using oxytocin in previous CS
Management
Maternal resuscitation
Blood: clotting, Hb, X-match
Urgent laparotomy (deliver fetus & cessation of bleeding)
If the liquor turns green or brown, what does this suggest?
The baby has passed meconium which is in response to vagal stimulation. Can be a sign of post dates to fetal distress.
What are the aim for contracting in first and second stages of labour?
Stage 1: 3-4 in 10 minutes
Stage 2: regular contractions lasting for 1 minute with 1 minute gaps.
What are the criteria for instrumental vaginal delivery?
Cervix is fully dilated & membrane ruptured
Position of head known (correct positioning of forceps/ventouse)
Head must not be palpable abdominally
Head at/below ischial spines on vaginal examination
Adequate analgesia
Bladder should be empty
Valid indication for delivery
Describe how Neville Barnes and Keillands forceps differ?
Neville barns are non-rotational forceps for the mid-cavity. They are used in OA position. (sagittal suture felt OA). They are shorted and more curved blade/
Kiellands are for rotational delivery and are therefore more flat.
