Labour and Delivery Flashcards
When do labour and delivery normally occur?
between 37-42 weeks gestation
What are the three stages of labour?
first stage = from onset of labour (true contractions) until 10 cm cervical dilatation
second stage = from 10cm cervical dilatation until delivery of the baby
third stage = from delivery of the baby until delivery of the placenta
What are the three phases of the first stage of labour?
latent phase = from 0 to 3cm dilation of the cervix, progresses at around 0.5cm per hour, irregular contractions
active phase = from 3cm to 7cm dilation of the cervix, progresses at around 1cm per hour, regular contractions
transition phase = from 7cm to 10cm dilation of the cervix, progresses at around 1cm per hour, strong and regular contractions
What are the signs of labour?
show (mucus plug from the cervix)
rupture of membranes
regular, painful contractions
dilating cervix on examination
How is prematurity classified?
<28 weeks = extreme preterm
28-32 weeks = very preterm
32-37 weeks = moderate to late preterm
What are the prophylactic options for preterm labour and who gets them?
vaginal progesterone = cervical length <25mm on vaginal US between 16 and 24 weeks
cervical cerclage (stitch in cervix under anaesthetic) = cervical length <25mm on vaginal US between 16-24 weeks, previous premature birth, cervical trauma
How is rupture of the membrane diagnosed?
speculum examination revealing pooling of amniotic fluid in the vagina
insulin-like growth factor-binding protein-1 or placental alpha-microglobin-1 (PAMG-1) can be performed to confirm
What is the management of preterm prelabour rupture of membranes?
prophylactic antibiotics to prevent chorioamnionitis = erythromycin for 10 days
induction of labour offered from 34 weeks
How is preterm labour with intact membranes diagnosed?
<30 weeks = clinical assessment
> 30 weeks = transvaginal US to assess the cervical length - cervical length <15 indicates preterm labour
foetal fibronectin is an alternative to US - <50ng/ml = preterm labour unlikely
What are the options for improving the outcomes in preterm labour?
foetal monitoring
tocolysis (use of medications to stop uterine contractions)
maternal corticosteroids offered before 35 weeks to reduce neonatal morbidity and mortality
IV magnesium sulphate before 34 weeks to protect the foetus’s brain
delayed cord clamping or cord milking to increase circulating blood volume and haemoglobin
What are the medications that are used in tocolysis?
1st line = nifedipine (CCB)
2nd line = atosiban (oxytocin receptor antagonist)
When is tocolysis used?
24-33+6 in preterm labour to delay delivery and buy time for further foetal development, administration of maternal steroids or transfer to a more specialist unit
only used for 48hrs max
When may induction of labour be offered?
41-42 weeks gestation
prelabour rupture of membranes
foetal growth restriction
pre-eclampsia
obstetric cholestasis
existing diabetes
intrauterine foetal death
What are the options for induction of labour?
membrane sweep
vaginal prostaglandin E2 (1st line)
cervical ripening ballon (2nd line)
artificial rupture of membranes with an oxytocin infusion (2nd line)
intrauterine foetal death = oral mifepristone plus misoprostol
What is the main complication of the induction of labour
uterine hyperstimulation
What are the criteria for uterine hyperstimulation?
individual uterine contractions lasting more than 2 minutes in duration
more than five uterine contractions every 10 minutes
What can uterine hyperstimulation lead to?
foetal compromise with hypoxia and acidosis
emergency C section
uterine rupture
What is the management of uterine hyperstimulation?
removing the vaginal prostaglandins or stopping the oxytocin infusion
tocolysis with terbutaline
What is cardiotocography (CTG) used to measure?
foetal heart rate
contractions of the uterus
What are the indications for continuous CTG monitoring during labour?
sepsis
maternal tachycardia (>120)
significant meoconium
pre-eclampsia
fresh antepartum haemorrhage
delay in labour
use of oxytocin
disproportionate maternal pain
What are the five key features to look for on a CTG?
contractions = number of uterine contractions per 10 minutes
baseline rate = baseline foetal heart rate
variability = how the foetal heart rate varies up and down around the baseline
accelerations = periods where the foetal heart rate spikes
decelerations = periods where the foetal heart rate drops
What are the reassuring, non-reassuring and abnormal baseline rates on a CTG?
reassuring = 110-160
non-reassuring = 100-109 or 161-180
abnormal = <100 or >180
What are is the reassuring, non-reassuring and abnormal variability on a CTG?
reassuring = 5-25
non-reassuring = <5 for 30-50 minutes or >25 for 15-25 minutes
abnormal = <5 for >50 minutes or >25 for <25 minutes
Why do decelerations occur?
foetal heart rate drops in response to hypoxia
What are early decelerations?
gradual dips and recoveries in foetal heart rate that correspond with uterine contractions - lowest point of the deceleration corresponds to the peak of the contraction
What causes early decelerations?
uterus compressing the foetal head - stimulates the vagus nerve - slows the heart rate
(not pathological)
What are late decelerations?
gradual falls in foetal heart rate that starts after the uterine contraction has begun - lowest point of deceleration occurs after the peak of the contraction
What causes late decelerations?
hypoxia in the foetus
can be due to:
excessive uterine contractions
maternal hypotension
maternal hypoxia
What are variable decelerations?
abrupt decelerations that may be unrelated to uterine contractions
fall of more than 15bpm from the baseline
lowest point occurs within 30 seconds and the decelerations lasts les than 2 minutes in total
What causes variable decelerations?
intermittent compression of the umbilical cord, causing foetal hypoxia
What is a reassuring sign in variable decelerations?
brief acceleration before and after the deceleration - known as shoulders - show that the foetus is coping
What are prolonged decelerations?
drop of more than 15bpm from baseline lasting between 2-10 minutes
What causes prolonged decelerations?
compression of the umbilical cord causing foetal hypoxia
What is the rule of 3 for prolonged foetal bradycardia?
3 minutes = call for help
6 minutes = move to theatre
9 minutes = prepare for delivery
12 minutes = deliver the baby by 15 minutes
What is a good structure for CTG interpretation?
DR C BRaVADO
Define Risk (risk based on the individual patient and pregnancy before assessing the CTG)
Contractions (duration, intensity, number in 10 minutes)
Baseline Rate (average foetal heart rate over 10 minutes)
Variability
Accelerations
Decelerations
Overall impression
What is one big square on a CTG chart equal to?
one minute
What is foetal tachycardia?
baseline heart rate >160bpm
What are the causes of foetal tachycardia?
foetal hypoxia
chorioamnionitis
hyperthyroidism
foetal or maternal anaemia
foetal tachyarrhythmia
What is foetal bradycardia?
baseline HR <110bpm
When is it common to have a baseline foetal heart rate of 100-120bpm?
postdate gestation
occiput posterior or transverse presentations
What is severe prolonged foetal bradycardia?
<80bpm for more than 3 minutes
What are the causes of prolonged severe foetal bradycardia?
prolonged cord compression
cord prolapse
epidural and spinal anaesthesia
maternal seizures
rapid foetal descent
What can cause reduced variability?
foetal sleeping (most common cause, shouldn’t last longer than 40 minutes)
foetal acidosis
foetal tachycardia
drugs - opiates, benzodiazepines, methyldopa, magnesium sulphate
prematurity
congenital heart abnormalities
What are the characteristics of a sinusoidal pattern on CTG?
smooth, regular, wave-like pattern
frequency of around 2-5 cycles a minute
stable baseline rate around 120-160bpm
no beat to beat variabilty
What does a sinusoidal pattern on CTG indicate?
severe foetal hypoxia
severe foetal anaemia
foetal or maternal haemorrhage
What are infusions of oxytocin used for?
induce labour
progress labour
improve the frequency and strength of uterine contractions
prevent or treat postpartum haemorrhage
What is the MOA of ergometrine?
stimulates smooth muscle contraction in the uterus and blood vessels
What is ergometrine used for?
during the third stage to deliver the placenta
postpartum to prevent and treat postpartum haemorrhage
(only used AFTER the delivery of the baby)
What are the side effects of ergometrine?
hypertension
diarrhoea
vomiting
angina
What are the contraindications to ergometrine?
eclampsia
hypertension (only used with significant caution)
What is syntometrine?
combination drug containing oxytocin (Syntocinon) and ergometrine
What can syntometrine be used for?
prevention or treatment of postpartum haemorrhage
What is a key prostaglandin to be aware of?
dinoprostone (prostaglandin E2)
What are the forms of dinoprostone?
vaginal pessaries (Propess)
vaginal tablets (Prostin tablets)
vaginal gel (Prostin gel)
What the MOA of nifedipine?
reduces smooth muscle contraction in blood vessels and the uterus
What are the main uses of nifedipine in pregnancy?
reduce blood pressure in hypertension and pre-eclampsia
tocolysis in premature labour - suppresses uterine activity and delays the onset of labour
What is the MOA of terbutaline?
beta-2-agonist - acts on the smooth muscle of the uterus to suppress uterine contractions
What is terbutaline used for?
tocolysis in uterine hyperstimulation - notably when the uterine contractions become excessive during induction of labour
What is the MOA of carboprost?
synthetic prostaglandin analogue - stimulates uterine contraction
What is carboprost used for?
deep IM injection in PPH where ergometrine and oxytocin have been inadequate
What is the contraindication to carboprost?
asthma
What is the MOA of tranexamic acid?
anti-fibrinolytic
binds to plasminogen and prevents it converting to plasmin
plasmin is an enzyme that works to dissolve the fibrin within blood clots
fibrin is a protein that helps hold blood clots together
prevents breakdown of blood clots
What is tranexamic acid used for in pregnancy?
prevention of postpartum haemorrhage
What influences progress in labour?
four Ps:
Power (uterine contractions)
Passenger (size, presentation and position of the baby)
Passage (shape and size of the pelvis and soft tissues)
Psyche (support and antenatal preparation for labour and delivery)
When is delay in first stage of labour considered?
<2cm of cervical dilatation in 4 hours
slowing of progress in a multiparous woman
What is used to monitor progress during the first stage of labour?
partogram
What is recorded on a partogram?
cervical dilatation (measured by a 4-hourly vaginal examination)
descent of the foetal head (in relation to the ischial spines)
maternal pulse, blood pressure, temperature and urine output
foetal heart rate
frequency of contractions
status of the membranes, presence of liquor and whether the liquor is stained by blood or meconium
drugs and fluids that have been given
What is crossing the alert line on a partogram an indication for?
amniotomy (artificially rupturing the membranes) and a repeat examination in 2 hours
What is crossing the action line on a partogram an indication for?
escalation to obstetric-led care
When is there considered to be a delay in the second stage of labour?
when active second stage (pushing) lasts over:
2 hours in a nulliparous woman
1 hour in a multiparous woman
What is a longitudinal lie?
foetus is straight up and down
What is a transverse lie?
foetus is straight side to side
What is an oblique lie?
foetus is at an angle
What is cephalic presentation?
head is first
What is shoulder presentation?
shoulder is first
What is a breech presentation?
legs are first
What are the types of breech presentation?
complete breech = hips and knees flexed (like doing a cannonball jump into a pool)
frank breech = hips flexed and knees extended, bottom first
footling breech = foot hanging through the cervix
What is delay in third stage of labour defined as?
more than 30 minutes with active management
more than 60 minutes with physiological management
What are the management options of failure to progress?
amniotomy/artificial rupture of membranes (ARM)
oxytocin infusion
instrumental delivery
C section
What simple analgesia can be used during early labour?
paracetamol +/- codeine
AVOID NSAIDs
What is gas and air (Entonox) composed of?
50% nitrous oxide and 50% oxygen
What is gas and air used for during labour?
short term relief of pain during contractions
What are the side effects of gas and air?
lightheadedness
nausea
sleepiness
What opioid medications can be used during labour?
IM pethidine or diamorphine
What are the side effects of opioids during labour?
mother = drowsiness, nausea
neonate = respiratory depression
may make first feed more difficult
What patient controlled analgesia may be used during labour?
IV remifentanil
What does an epidural involve?
insertion of a small tube (catheter) into epidural space in the lower back (outside the dura mater, separate from the spinal cord and CSF)
infusion of local anaesthetic
What drugs are used in an epidural?
levobupivacaine or bupivacaine - usually mixed with fentanyl
What are the adverse effects of an epidural?
headache after insertion
hypotension
motor weakness in the legs
nerve damage
prolonged second stage
increased probability of instrumental delivery
What is cord prolapse?
umbilical cord descends below the presenting part of the foetus and through the cervix into the vagina, after rupture of the foetal membranes
What is the significant risk of cord prolapse?
foetal hypoxia
What is the most significant risk factor for cord prolapse?
foetus is in an abnormal lie after 37 weeks gestation
What is the management of a cord prolapse?
emergency C section
whilst waiting for C section:
keep cord warm and wet with minimal handling
if baby is compressing the cord, push the presenting part upwards
pregnant person can lie in the left lateral position (with a pillow under the hip) or the knee-chest position (on all fours) using gravity to draw foetus away from the pelvis and reduce compression on the cord
tocolytic medication to minimise contractions
What is shoulder dystocia?
anterior shoulder of the baby becomes stuck behind the pubic symphysis of the pelvis after the head has been delivered
What is the most common cause of shoulder dystocia?
macrosomia secondary to gestational diabetes
What is the presentation of shoulder dystocia?
difficulty delivering face and head
obstruction in delivering the shoulders
failure of restitution (head remains face downwards and does not turn sideways as expected)
turtle-neck sign (head is delivered but then retracts back into the vagina)
What techniques may be used to management shoulder dystocia and deliver the baby?
episiotomy - enlarges the vaginal opening and reduces the risk of perineal tears
McRoberts manoeuvre - hyperflexion of the pregnant person at the hip (bringing her knees to her abdomen) to provide a posterior pelvic tilt which lifts the pubic symphysis up and out of the way
pressure to the anterior shoulder by pressing on the suprapubic region of the abdomen
Rubins manoeuvre - reaching into the vagina to put pressure on the posterior aspect of the baby’s anterior shoulder
Wood’s screw manoeuvre - during a Rubins manoeuvre, the other hand is reached into the vagina to put pressure on the anterior aspect of the posterior shoulder to rotate the baby
Zavanelli manoeuvre - pushing the baby’s head back into the vagina so it can be delivered by emergency C-section
What are the key complications of shoulder dystocia?
foetal hypoxia (and subsequent cerebral palsy)
brachial plexus injury and Erb’s palsy
perineal tears
PPH
What is given after instrumental delivery to reduce the risk of maternal infection?
single dose of co-amoxiclav
What are the indications for an instrumental delivery?
failure to progress
foetal distress
maternal exhaustion
control of the head in various foetal positions
What increases the risk of requiring an instrumental delivery?
epidural
What are the risks to the mother of an instrumental delivery?
PPH
episiotomy
perineal tears
injury to anal sphincter
incontinence of the bladder or bowel
nerve injury - obturator or femoral
What are the risks to the baby of an instrumental delivery?
key risks = cephalohaematoma (collection of blood between the skull and the periosteum) with ventose, facial nerve palsy with forceps
rare but serious risks = subgaleal haemorrhage, intracranial haemorrhage, skull fracture, spinal cord injury
What nerve injuries can being in the lithotomy position cause?
lateral cutaneous nerve of the thigh
common peroneal nerve
What can cause lumbosacral plexus injury during labour?
compression by foetal head during the second stage
What increases the risk of a perineal tear?
first births (nulliparity)
large babies (over 4kg)
shoulder dystocia
Asian ethnicity
occipito-posterior position
instrumental deliveries
What is a first degree perineal tear?
injury limited to the frenulum of the labia minora (where they meet posteriorly) and superficial skin
What is a second degree perineal tear?
includes the perineal muscles but not the anal sphincter
What is a third degree perineal tear?
includes the anal sphincter but not the rectal mucosa
What is a fourth degree perineal tear?
includes the rectal mucosa
How are third-degree perineal tears subcategorised?
3A = <50% of the external anal sphincter affected
3B = >50% of the external anal sphincter affected
3C = external and internal anal sphincter affected
What is the management of perineal tears?
second degree = sutures
third and first degree = repair in theatre
additional measures = broad-spectrum antibiotics, laxatives, physiotherapy, followup
What are the possible short term complications after a perineal tear?
pain
infection
bleeding
wound dehiscence or breakdown
What are the potential long term complications of perineal tears?
urinary incontinence
anal incontinence and altered bowel habit (3rd and 4th degree)
fistula between the vagina and bowel
sexual dysfunction and dyspareunia (painful sex)
psychological and mental health consequences
What is a mediolateral episiotomy?
cut made around 45 degrees diagonally from the opening of the vagina downwards and laterally to avoid damaging the anal sphincter
What can be done to reduce the risk of perineal tears?
perineal massage from 34 weeks onwards
What is physiological management of the third stage?
placenta is delivered by maternal effort without medications or cord traction
What is the benefit of active management of the third stage?
shortens the third stage
reduces the risk of bleeding
What are the side effects of active management of the third stage?
nausea and vomiting
What are the indications for active management of the third stage?
maternal choice
haemorrhage
>60 minute delay in delivery of the placenta (prolonged third stage)
What is involved in active management of the third stage?
IM oxytocin after delivery of baby
cord is clamped and cut within 1-5 minutes of birth
controlled cord traction during uterine contraction with other pressing the uterus upwards to prevent prolapse
after delivery, uterus is massaged until it is contracted and firm
What is the definition of a PPH?
> 500ml after a vaginal delivery
1000ml after a C section
What are the causes of postpartum haemorrhage?
4 Ts
Tone - uterine atony (failure to contract, most common)
Trauma
Tissue - retained placenta
Thrombin - bleeding disorder
What are the risk factors for PPH?
previous PPH
multiple pregnancy
obesity
large baby
failure to progress in the second stage of labour
prolonged third stage
pre-eclampsia
placenta accreta
retained placenta
instrumental delivery
general anaesthesia
episiotomy or perineal tear
What can be done to reduce the risk and consequences of a PPH?
treating anaemia during the antenatal period
giving birth with an empty bladder (full bladder reduces uterine contraction)
active management of third stage
IV tranexamic acid in the third stage of a section in high risk patients
What are the mechanical treatment options for PPH?
rubbing the uterus through the abdomen to stimulates a uterine contraction (referred to as rubbing up the fundus)
catheterisation (bladder distention prevents uterine contractions)
What are the medical treatment options for PPH?
oxytocin (slow injection followed by continuous infusion)
ergometrine (IV or IM) - stimulates smooth muscle contraction (contraindicated in hypertension)
carboprost (IM) - prostaglandin analogue that stimulates uterine contraction (caution in asthma)
misoprostol (sublingual)
tranexamic acid (IV)
What are the surgical treatment options for PPH?
intrauterine balloon tamponade (inserting an inflatable balloon into the uterus to press against the bleeding)
B-lynch suture (putting a suture around the uterus to compress it)
uterine artery ligation
hysterectomy
What is a secondary PPH?
bleeding occurs from 24 hours to 12 weeks postpartum
What are the causes of secondary PPH?
retained products of conception
infection
What investigations should be carried out for secondary PPH?
US for retained products of conception
endocervical and high vaginal swabs for infection
What are the indications for an elective C section?
previous C section
symptomatic after a previous significant perineal tear
placenta praevia
vasa praevia
breech presentation
multiple pregnancy
uncontrolled HIV infection
cervical cancer
What are the categories of an emergency C section?
category 1 = immediate threat to the life of the mother or baby, decision to delivery time is 30 minutes
category 2 = there is not an imminent threat to life but caesarean is required urgently due to compromise of the mother or baby, decision to delivery time is 75 minutes
category 3 = delivery is required but mother and baby are stable
category 4 = elective C section
What are the two types of C section incisions?
Pfannenstiel incision = curved incision two fingers width above the pubic symphysis
Joel-cohen incision = straight incision that is slightly higher (recommended incision)
What are the measures to reduce the risks during C section?
H2 receptor antagonists or PPIs
prophylactic antibiotics
oxytocin
LMWH
What are the effects of a C section on future pregnancies?
increased risk of:
repeat C section
uterine rupture
placenta praevia
stillbirth
What is the success rate of VBAC?
75%
What is the uterine rupture risk in VBAC?
0.5%
What are the contraindications to VBAC?
previous uterine rupture
classical C section scar (a vertical incision)
other usual contraindications to vaginal delivery
What are the two key causes of sepsis in pregnancy?
chorioamnionitis
UTIs
What are the features of chorioamnionitis?
abdominal pain
uterine tenderness
vaginal discharge
What are the risk factors for amniotic fluid embolus?
increasing maternal age
induction of labour
C section
multiple pregnancy
What is the presentation of an amniotic fluid embolism?
shortness of breath
hypoxia
hypotension
coagulopathy
haemorrhage
tachycardia
confusion
seizures
cardiac arrest
What are the risk factors for uterine rupture?
VBAC
previous uterine surgery
increased BMI
high parity
increased age
induction of labour
use of oxytocin to stimulate contractions
What is the presentation of uterine rupture?
abdominal pain
vaginal bleeding
ceasing of uterine contractions
hypotension
tachycardia
collapse
What is uterine inversion?
fundus of the uterus drops down through the uterine cavity and cervix
What are the management options for uterine inversion?
1st line = Johnson manoeuvre (using a hand to push the fundus back up into the abdomen and the correct position)
2nd line = hydrostatic methods (filling the vagina with fluid to inflate the uterus back into the normal position
3rd line = surgery
What are the risks of prematurity?
increased mortality
respiratory distress syndrome
intraventricular haemorrhage
necrotizing enterocolitis
chronic lung disease, hypothermia, feeding problems, infection and jaundice
retinopathy of prematurity
hearing problems
What is the management of placental abruption?
foetus alive and <36 weeks:
foetal distress = immediate C section
no foetal distress = steroids, admission, observation
foetus alive and >36 weeks:
foetal distress = immediate C section
no foetal distress = deliver vaginally
foetus dead = induce vaginal delivery
What are the requirements for an instrumental delivery?
FORCEPS
Fully dilated cervix
OA position preferably
Ruptured membranes
Cephalic presentation
Engaged presenting part
Pain relief
Sphincter (bladder) empty
Give examples of indications for category 1 C sections
suspected uterine rupture
major placental abruption
cord prolapse
foetal hypoxia
persistent foetal bradycardia
What are the components of the Bishop score?
cervical position:
posterior = 0
intermediate = 1
anterior = 2
cervical consistency:
firm = 0
intermediate = 1
soft = 2
cervical effacement:
0-30% = 0
40-50% = 1
60-70% = 2
80% = 3
cervical dilation:
<1cm = 0
1-2 cm = 1
3-4cm = 2
>5 cm = 3
foetal station:
-3 = 0
-2 =1
-1, 0 = 2
+1, +2 = 3
What does a Bishop score less than 5 indicate?
labour is unlikely to start without induction
What does a Bishop score of 8 or more indicate?
cervix is ripe/favourable - high change of spontaneous labour or response to interventions made to induce labour
How should labour be induced if the Bishop score is 6 or less?
first line = vaginal porstaglandins or oral misoprostol
mechanical methods (e.g. balloon catheter) can be considered if the woman is at higher risk of hyperstimulation or has had a previous section
How should labour be induced if the Bishop score is greater than 6?
amniotomy
IV oxytocin infusion
What is the presentation of false labour?
occurs in the last 4 weeks of pregnancy
contractions felt in the lower abdomen
contractions are irregular and occur about every 20 minutes
progressive cervical changes are absent
