Labour Flashcards
Labour may be defined as
onset of regular and painful contractions associated with cervical dilation and descent of the presenting part
Signs of labour include
regular and painful uterine contractions
a show (shedding of mucous plug)
rupture of the membranes (not always)
shortening and dilation of the cervix
Labour may be divided in to three stages which are:
stage 1: from the onset of true labour to when the cervix is fully dilated
stage 2: from full dilation to delivery of the fetus
stage 3: from delivery of fetus to when the placenta and membranes have been completely delivered
Monitoring in Labour
FHR monitored every 15min (or continuously via CTG)
Contractions assessed every 30min
Maternal pulse rate assessed every 60min
Maternal BP and temp should be checked every 4 hours
VE should be offered every 4 hours to check progression of labour
Maternal urine should be checked for ketones and protein every 4 hours
Stage 1 - from the onset of true labour to when the cervix is fully dilated. In a primigravida lasts typical
10-16 hours
Stage 1 phases?
latent phase = 0-3 cm dilation, normally takes 6 hours
active phase = 3-10 cm dilation, normally 1cm/hr
?% of babies are vertex at present
90%
Head enters pelvis in ?position. The head normally delivers in an ?position.
Head enters pelvis in occipito-lateral position. The head normally delivers in an occipito-anterior position.
Labout stage 2 different parts of second stage?
‘passive second stage’ refers to the 2nd stage but in the absence of pushing (normal)
active second stage’ refers to the active process of maternal pushing
Which stage is most painful 1 or 2
1 as pushing masks pain
Stage 2 lasts approximately ?
What to do if longer than this?
1 hours
if longer than 1 hour (can be left longer if epidural) consider Ventouse extraction, forceps delivery or caesarean section
in stage 2 episiotomy may be necessary following crowning
true
Stage 2 is associated with transient fetal tachy/bradycardia
bradycardia
Induction of labour describes a process where labour is started artificially. It happens in around ?% of pregnancies
Induction of labour describes a process where labour is started artificially. It happens in around 20% of pregnancies
Induction of labour , Indications
prolonged pregnancy, e.g. > 12 days after estimated date of delivery
prelabour premature rupture of the membranes, where labour does not start
diabetic mother > 38 weeks
rhesus incompatibility
Induction of labour methods?
membrane sweep
intravaginal prostaglandins
breaking of waters
oxytocin
Cardiotocography (CTG) records what?
pressure changes in the uterus using internal or external pressure transducers
The normal fetal heart rate varies between
100-160 / min
<100 brady, >160 tachy
Baseline fetal bradycardia causes
Increased fetal vagal tone, maternal beta-blocker use
Baseline fetal tachycardia causes
Maternal pyrexia, chorioamnionitis, hypoxia, prematurity
Loss of baseline variability is what?
Causes?
< 5 beats / min
Prematurity, hypoxia
What is Early deceleration
Deceleration of the heart rate which commences with the onset of a contraction and returns to normal on completion of the contraction
What is Early deceleration caused by
Usually an innocuous feature and indicates head compression
What is late deceleration
Deceleration of the heart rate which lags the onset of a contraction and does not returns to normal until after 30 seconds following the end of the contraction
What is late deceleration caused by
Indicates fetal distress e.g. asphyxia or placental insufficiency
Variable decelerations are Independent of contractions
true
Variable decelerations may indicate
cord compression
Risk factors for perineal tears
primigravida large babies precipitant labour shoulder dystocia forceps delivery
The RCOG has produced guidelines suggesting the following classification of perineal tears?
first degree: superficial damage with no muscle involvement
second degree: injury to the perineal muscle, but not involving the anal sphincter
third degree: injury to perineum involving the anal sphincter complex (external anal sphincter, EAS and internal anal sphincter, IAS):
Describe the sub classifications of third degree perineal tears
3a: less than 50% of EAS thickness torn
3b: more than 50% of EAS thickness torn
3c: IAS torn
fourth degree: injury to perineum involving the anal sphincter complex (EAS and
IAS) and rectal mucosa
Preterm prelabour rupture of the membranes (PPROM) occurs in around ?% of pregnancies but is associated with around ?% of preterm deliveries
Preterm prelabour rupture of the membranes (PPROM) occurs in around 2% of pregnancies but is associated with around 40% of preterm deliveries
Complications of PPROM
fetal: prematurity, infection, pulmonary hypoplasia
maternal: chorioamnionitis
Ix PPROM
A sterile speculum examination should be performed (to look for pooling of amniotic fluid in the posterior vaginal vault)
Ultrasound may also be useful to show oligohydramnios.
PPROM - digital exam indicated
digital examination should be avoided due to the risk of infection
PPROM Mx
admission
regular observations to ensure chorioamnionitis is not developing
oral erythromycin should be given for 10 days
antenatal corticosteroids should be administered to reduce the risk of respiratory distress syndrome
delivery should be considered at 34 weeks of gestation
PPROM - why should delivery be considered at 34 weeks of gestation
there is a trade-off between increased risk of maternal chorioamnionitis with a decreased risk of respiratory distress syndrome as the pregnancy progresses
which score is used to help assess the whether induction of labour will be required?
The Bishop score
components of bishop score?
Cervical position Cervical consistency Cervical effacement Cervical dilation Fetal station
Each component can have 0-3 points or 0-2
Interpretation of bishop score?
a score of < 5 indicates that labour is unlikely to start without induction
a score of > 9 indicates that labour will most likely commence spontaneously
Descibe scoring for Cervical position in Bishop score?
Posterior 0
Intermediate 1
Anterior 2
Descibe scoring for Cervical consistency in Bishop score?
Firm 0
Intermediate 1
Soft 2
Descibe scoring for Cervical effacement in Bishop score?
0-30% 0
40-50% 1
60-70% 2
80% 3
Descibe scoring for Cervical dilation in Bishop score?
<1 cm = 0
1-2 cm = 1
3-4 cm = 2
>5 cm = 3
Descibe scoring for Fetal station in Bishop score?
-3 (0 point)
-2 (1 point)
-1,0 (2 point)
+1,+2 (3 point)
The World Health Organization defines a post-term pregnancy as
one that has extended to or beyond 42 weeks.
Post-term pregnancy
Potential complications/consequences:
Neonatal?
Reduced placental perfusion
Oligohydramnios
Post-term pregnancy
Potential complications/consequences:
Maternal?
Increased rates of intervention including forceps and caesarean section
Increased rates of labour induction
Shoulder dystocia is
complication of vaginal cephalic delivery. It entails inability to deliver the body of the fetus using gentle traction, the head having already been delivered. Shoulder dystocia is a cause of both maternal and fetal morbidity.
It usually occurs due to impaction of the anterior fetal shoulder on the maternal pubic symphysis
Shoulder dystocia complications?
postpartum haemorrhage and perineal tears with respect to the former, and brachial plexus injury with respect to the latter, amongst other complications. Neonatal death occasionally occurs.
Key risk factors for shoulder dystocia include
fetal macrosomia, high maternal body mass index, diabetes mellitus and prolonged labour.
shoulder dystocia mx
help should be called as soon as shoulder dystocia is identified and McRoberts’ manoeuvre should be performed. This manoeuvre entails flexion and abduction of the maternal hips, bringing the mother’s thighs towards her abdomen. This rotation increases the relative anterior-posterior angle of the pelvis and often facilitates a successful delivery.
An episiotomy will not relieve the bony obstruction but is sometimes used to allow better access for internal manoeuvres.
Oxytocin administration is not indicated in shoulder dystocia.
true
Symphysiotomy and the Zavanelli manoeuvre can cause significant maternal morbidity and are not first-line options in shoulder dystocia
true
Cord prolapse is
involves the umbilical cord descending ahead of the presenting part of the fetus
Cord prolapse complications?
Left untreated, this can lead to compression of the cord or cord spasm, which can cause fetal hypoxia and eventually irreversible damage or death.
Risk factors for cord prolapse include:
prematurity multiparity polyhydramnios twin pregnancy cephalopelvic disproportion abnormal presentations e.g. Breech, transverse lie placenta praevia long umbilical cord high fetal station
The majority of cord prolapses occur at
artificial rupture of the membranes.
Diagnosis cord prolapse?
The diagnosis is usually made when the fetal heart rate becomes abnormal and the cord is palpable vaginally, or if the cord is visible beyond the level of the introitus.
cord prolapse mx
For management of cord prolapse, the presenting part of the fetus may be pushed back into the uterus to avoid compression.
Tocolytics may be used.
If the cord is past the level of the introitus, it should be kept warm and moist but should not be pushed back inside.
The patient is asked to go on ‘all fours’ until preparations for an immediate caesarian section have been carried out.
Although this is the usual first-line method of delivery, an instrumental vaginal delivery is possible if the cervix is fully dilated and the head is low. If treated early, fetal mortality in cord prolapse is low.
Incidence of cord prolapse is reduced by
reduced by the increase in caesarian sections being used in breech presentations.
