Normal labour and delivery Flashcards
What is the definition of the onset of labour?
the point when uterine contractions become regular and cervical effacement (thinning) and dilatation becomes progressive
What is labour?
the process by which the fetus is delivered after the 24th week of gestation
What is considered the duration of labour in clinical practice?
the duration of observed labour, no the duration the mother had painful contractions at home
How do show and rupture of membranes relate to labor?
they may or may not be associated with labour - in themselves, do not suggest onset of labour
What are 6 things that labour is characterised by in most cases?
- Onset of uterine contractions, which increase in frequency, duration, and strength over time.
- Cervical effacement and dilatation.
- Rupture of membranes with leakage of amniotic fluid.
- Descent of the presenting part through the birth canal.
- Birth of the baby.
- Delivery of the placenta and membranes.
What are 7 stages in the sequence for passage through the pelvic for a normal vertex delivery?
- Engagement and descent: the head enters the pelvic in the occipito-transverse position with increased flexion as it descends
- Internal rotation to occipitoanterior: occurs at level of ischial spines due to forward and downward sloping of levator ani muscles
- Crowning: head extends, distending the perineum until it is delivered
- Restitution: the head rotates so that the occiput is in line with the fetal spine
- External rotation: the shoulders rotate when they reach the levator muscles until the biacromial diameter is anteroposterior (head externally rotates by same amount)
- Delivery of anterior shoulder: occurs by lateral flexion of trunk posteriorly
- Delivery of posterior shoulder: occurs by lateral flexion of trunk anteriorly and rest of body follows
What is the definition of the first stage of labour?
onset of labour to full dilatation, divded into two phases: latent and active
What are the 2 phases that make up the first stage of labour?
- Latent phase: period taken for cervix to completely efface and dilate up to 4cm
- Active phase: regular painful contractions when the cervix dilates from 4cm to full dilatation (10cm)
What are Braxton-Hicks contractions?
Mild, often irregular, non-progressive contractions that may occur from 30 weeks gestation (more common after 36 weeks) and may often be confused with labour
How do Braxton-Hicks contractions compare with normal labour?
contractions in labour are painful, with a gradual increase in frequency, amplitude, and duration - Braxton Hicks are ore mild, irregular, non-progressive
When wouldn’t you clinically intervene with labour?
if progress is normal and there is no concern for the mother or the fetus
What are 2 things that should make you suspect failure to progress in the first stage of labour?
- There is <2cm dilatation in 4h (on a 4hr action line partogram the plotted progress falls to the right)
- Slowing in progress in parous women
What are the 2 terms given to type of dysfunction first stage of labour and what do they mean?
- Primary dysfunctional laboru: labour slow from onset
- Secondary arrest: if there was previous adequate progress
What are 4 causes of poor progress in the first stage of labour?
- Power: inefficient uterine activity
- Passenger: malpositions, malpresentation, or large baby
- Passage: inadequate pelvis
- Combination of two or more of the above
What are 5 parts of an assessment of poor progress in the first stage of labour?
- Review the history
- Abdominal palpation of, frequency, and duration of contractions
- Review fetal condition: fetal heart rate and colour/quantity of amniotic fluid
- Review maternal condition including hydration and analgesia
- Vaginal assessment: cervical effacement, dilatation, caput, moulding, position, and station of head
What are 4 options for management of poor progress in the first stage of labour?
- Amniotomy (i.e. artificial rupture of membranes [ARM]) and reassess in 2h
- Amniotomy + oxytocin infusion and reassess in 2h: this should always be considred in nulliparous women
- Lower segment CS (if there is fetal distress)
In which group of women with poor progress in the first stage of labour should amniotomy with oxytocin always be considered?
nulliparous women
When would you consider lower segment C-section in poor progression in the first stage of labour?
if there is fetal distress
What must be done before starting oxytocin in women with poor progression in the first stage of labour, who are multiparous and those with a previous CS?
experienced obstetrician should review before starting oxytocin
What are 6 vital parts of monitoring in labor?
- Fetal heart rate - every 15 minutes (or continuously with CTG)
- Assess contractions every 30 minutes
- Maternal pulse should be checked hourly
- BP and temperature should be checked 4 hourly
- VE should be offered every 4h to assess progress
- Maternal urine is tested 4-hourly or when passed for ketones and protein
How are all 6 vital parts of monitoring during labour recorded?
on the partogram - graphical representation of progress of labour
What is the definition of the second stage of labour?
time from full cervical dilatation until the baby is born
How long is usually allowed for passive descent of the baby before active pushing is commenced and what are the conditions of this?
1 hour - if woman has an epidural and the CTG is reassuring
In the hour between reaching full dilatation and beginning active pushing, what must be ensured?
good contractions are maintained and oxytocin may be commenced
Within what time frame from the start of the 2nd stage of labour must birth take place for 1. nulliparous women and 2. multiparous women?
- 3 hours
- 2 hours
When is the definition of the start of the active second stage of labour?
commences when mother starts expulsive efforts using her abdominal muscles with the Valsalva manoeuvre to ‘bear down’
What are 4 positions which women may choose to deliver?
- squatting
- standing
- on all fours
- supine
- lithotomy position, if instrumental - supine with legs flexed at 90 degrees
What are 3 steps to the normal second stage of labour?
- As head comes down, it distends perineum and anus - can use pad to support perineum and cover anuswhile other hand used to maintain flexion and prevent sudden deflexion and control rate of delivery of head
- With next contraction, gentle traction guides head towards perineum until anterior shoulder is delivered under suprapubic arch
- Cord double-clamped and cut
What is the purpose of using a pad to support the perineum and cover anus while using other hand to maintain flexion and prevent sudden deflexion during the second stage of labour?
control rate of delivery of head - attempts to slow perineal distension, minimising tears by preventing rapid delivery
Why might an episiotomy be performed in the second stage of labour?
if there is concern that the perineum is tearing towards the anal sphincter (shouldn’t be used routinely)
Why should you slightly delay cutting the umbilical cord following delivery of the baby?
delaying for 2-3 mins results in higher haematocrit levels in the neonate - allows physiological transfer of placental blood to infant
At what points following birth of the baby is it assessed and using what system?
1, 5, and 10 minutes
Apgar scoring system
(if all well, hand baby back to mother as soon as possible)
What is considered a delay in the second stage of labour in 1. nulliparous women and 2. multiparous women?
- Nulliparous: if delivery not imminent after 1 hour of active pushing
- Multiparous: if delivery not imminent after 1 hour of active pushing (i.e. same for both)
What should be done if there is a delay in the second stage of labour in nulliparous women (>1hr of active pushing)?
offer vaginal examination and amniotomy recommended
if not delivered in 2 hours: requires review by obstetrician to consider instrumental delivery or C-section
What should be done if there is a delay in the second stage of labour in multiparous women (>1hr of active pushing)?
requires review by obstetrician to consider instrumental delivery or CS (sooner than in nulliparous women)
What should you be suspicious of in a delay in the second stage of labour in a multiparous woman?
malposition or disproportion
What are 2 ways to manage the third stage of labour?
- Active management
- Physiological management
What is the definition of the third stage of labour?
the duration from delivery of the baby to delivery of the placenta and membranes
What 3 things does active management of the third stage of labour involve?
- Use of uterotonics (oxytocin, ergometrine, misoprostol)
- Clamping and cutting of the cord
- Controlled cord traction
What are 4 examples of uterotonic drugs?
- Ergometrine
- Ergometrin + oxytocin - Syntometrine
- Oxytocin
- Misoprostol (prostaglandin analogue)
What is meant by controlled cord traction in active management of the third stage of labour?
traction applied to the umbilical cord once the uterus has contracted after the birth of the baby, and placenta felt to have separated from the uterine wall, whilst counter pressure applied to uterus until placenta delivers
What are 4 benefits to an active as opposed to physiological management of the third stage of labour?
- Reduced rates of postpartum haemorrhage over 1L
- Reduced mean blood loss and postnatal anaemia
- Reduced length of the third stage
- Reduced need for blood transfusions
What are 2 adverse effects of active management of the third stage of labour?
- Nausea and vomiting
- Headache
What is physiological management of the third stage of labour? 5 aspects
- no syntometrine or oxytocin given (uterotonics)
- cord allowed to stop pulsating before clamped and cut - clamp for at least 1 minute, unless baby’s heart rate is <60bpm and not picking up
- Cord should be clamped before end of 5 minutes
- Placenta delivered by maternal effort alone
- Cord not pullsed, uterus not push on to help expel placenta
What are 3 things that mean a planned physiological 3rd stage of labour should be changed to active management?
- Haemorrhage
- Failure to deliver the placenta within 1h
- Maternal desire to shorten the 3rd stage
What are 5 steps to an actively managed third stage of labour?
- Syntometrine IM (ergometrine 0.5mg + oxytocin 5I) or oxytocin 10IU IM given as anterior shoulder of baby born
- Dish placed at introitus to collect placenta and any blood loss, and left hand is placed on the abdomen over the uterine fundus
- As uterus contracts to 20 week size, the placenta separates from the uterus through the spongy layer of the decidua basaline
- Uterus will then feel globular and firmer, cord will lengthen, there is often trickle of fresh blood (separation bleeding)
- Controlled cord traction (CCT) applied with right hand, whilst supporting fundus with left hand (Brandt-Anrew’s technique)
What is syntometrine?
ergometrine 0.5mg + oxytocin 5IU
What must be excluded before uterotonics are given in the third stage of labour?
multiple pregnancy (twins etc.)
What does NICE recommended is used at the uterotonic in the active management of the third stage of labour?
oxytocin 10IU rather than syntometrine - similar efficacy but with fewer side effects
When do most complications from childbirth occur?
in the first 2 hours after delivery
What are 3 key complications which occur in the 2 hours following delivery?
- Post-partum haemorrhage
- Uterine inversion
- Haematoma formation
What is done due to the high risk of complications from delivery in the following 2 hours?
women kept in delivery unit during this time to observe pulse, BP, temperature, uterine size and contractions, fresh bleeding PV, painful swelling of vulva, vagina or perineum
What are 7 things that are observed in the 2 hours following delivery when the woman if kept in the delivery unit?
- Blood pressure
- Pulse
- Temperature
- Uterine size
- Uterine contractions
- Fresh PV bleeding
- Swelling of vulva, vagina, perineum
What is an example of a factor that increases risk of PPH?
multiple pregnancy
What treatment should be given prophylactically following delivery if there is a high risk of PPH, and for how long?
oxytocin infusion - 40U in 500ml saline, given for 3-4 hours
What should be immediately encouraged in the first hour following delivery? 2 things
- skin-to-skin contact, baby and other shouldn’t be separated for 1st hour
- breastfeeding - should be initiated in first hour
What can be done following the first 2 hours of monitoring if there are no complications following deliver?
mother may be transferred to postnatal ward; some women may then go home after further 3-4 hours of observation
What proportion of all pregnancies are induced?
10-20%
What is the success rate of inductions of labour at term?
60-80%
What are 2 types of indications for induction of labour?
obstetric or medical
What is the chance of achieving a vaginal birth after induction of labour before 34 weeks gestation?
35%
What should the response be to induction of labour on maternal request?
should be avoided as associated with risks for both mother and fetus
What are 11 obstetric indications for induction of labour?
- Uteroplacental insufficiency
- Prolonged pregnancy (41-42 weeks)
- FGR
- Oligo- or anhydramnios
- Abnormal uterine or umbilical artery Dopplers
- Non-reassuring CTG
- PROM
- Severe pre-eclampsia or eclampsia after maternal stabilisation
- Intrauterine death of the fetus (IUD)
- Unexplained antepartum haemorrhage at term
- Chorioamnionitis
Should induction be used in suspected fetal macrosomia?
no, inadequate evidence - some advocate 40-41 weeks to prevent further intrauterine growth and associated risks (shoulder dystocia, birth trauma)
What is meant by medical indications for induction of labour?
underlying maternal medical conditions - maternal risks may be limited with induction (balance interests of mother with risks of prematurity)
What are 4 examples of medical indications of induction of labour?
- Severe hypertension
- Uncontrolled diabetes mellitus
- Renal disease with deteriorating renal function
- Malignancies (to facilitate definitive therapy)
What are 3 strong predictors for a successful induction of labour?
- Gestational age at induction
- Parity
- Modified Bishop’s score of the cervix - overview of the ‘ripeness’ of the cervix
What are 6 things taken into account by the Modified Bishop’s score of the cervix to assess ripeness of the cervix?
- Position of cervix
- Length of cervix
- Consistency of cervix
- Dilatation of cervix
- Station of the presenting part (distance in cm in relation to ischial spines)
What is meant by cervical ripening?
change of cervix from being closed and firm to being soft and thin; softening before dilatation occurs prior to onset of labour contractions
What are 2 types of methods to bring about cervical ripening?
- Mechanical
- Pharmacological
What are 2 types of mechanical methods of cervical ripening?
- Artificial separation: ‘stretch and sweep’
- Single and double balloon catheters
What does artificial separation to achieve cervical ripening involve?
cervical os admits a finger, involves digitally separating the membranes from the cervix, leading to local release of prostaglandins
What is the success rate of artificial separation to achieve cervical ripening?
30% will go into spontaneous labour in <7 days; results in a more favourable cervix in the majority
What are the drawbacks of artificial separation to achieve cervical ripening?
uncomfortable, may cause some bleeding
What is a drawback of using single and double balloon catheter in clinical practice?
take a longer induction to delivery interval
What are 3 pharmacological methods to achieve cervical ripening?
- Prostaglandins (PGE2 = dinoprostone)
- Misoprostol
- Oxytocin infusion
What are the preferred agents for cervical ripening?
prostaglandins (PGE2= dinoprostone)
How are prostaglandins usually given to achieve cervical ripening?
intravaginally into the posterior fornix; gel 2mg or tablet 3mg
What is a benefit of the gel form of prostaglandins for cervical ripening?
absorbed well
What is a benefit of the tablet form of prostaglandins for cervical ripening?
can be easily removed if hyperstimulation occurs (5-7% of cases)
What is the name of the slow-release form of PGE2 which is available for cervical ripening and how is this used?
- Propess
- PGE2 is in a satchel with a tail for easy removal, should there be hyperstimulation
- Pessary left in situ for 24 hours
What are the effects of using a Propess pessary for cervical ripening?
reduced inducton to delivery interals and slightly reduced instrumental vaginal delivery rates, but no difference in CS rates
In addition to prostaglandins what is another example of a medication that can be given for cervical ripening?
Misoprostol
How can misoprostal be used to achieve cervical ripening?
25mcg orally every 2 hours or vaginally every 6 hours
What is an advantage and 2 drawbacks of using misoprostol for cervical ripening?
- Adv: higher success rate in achieving vaginal delivery
- Disadv:
- higher incidence of hyperstimulation and passage of meconium by fetus
- contraindicated in some women with a Caesarean scar
What is the method of oxytocin infusion to achieve cervical ripening?
shown to increase cervical prostaglandin levels; as most receptors located in myometrium, more suitable for initiating uterine contractions
In what situation is it best to oxytocin infusion?
where membranes have ruptured, whether spontaneously or after amniotomy
What are 3 methods to achieve induction of labour?
- Amniotomy (or artificial rupture of membranes, ARM) ± oxytocin infusion
- Prostaglandin insertion
- Synthetic oxytocin
How does amniotomy (artificial rupture of membranes) bring about induction of labour?
releases local prostaglandins causing cervical ripening and myometrial contractions
When should you commence oxytocin infusion following amniotomy?
If regular, painful uterine contractions are not initiated or there are no cervical changes after 2 hours → commence infusion
What is the benefit of starting oxytocin at the time of amniotomy?
shown to decrease the induction-delivery interval, decreasing both fetal and maternal risk of sepsis
What monitoring should be performed when using prostaglandins for induction of labour and why?
- CTG 30 min before and after insertion of prostaglandins, to confirm fetal well-being and to detect possible hyperstimulation
- VE after 6 hours to assess cervix
What should be done if vaginal examination following prostaglandin insertion for induction of labour shows an unfavourable cervix after 6 hours?
another dose may be administered
rare that multiparous women require more than 1
When do you need a consultant to review administration of prostaglandins for induction of labour?
if >2 doses planned to be given
What drug shouldn’t you start immediately after giving prostaglandins for induction of labour and why? When can it be given?
Oxytocin to avoid risk of uterine hyperstimulation
shouldn’t be started for 6 hours after
How should synthetic oxytocin for induction or augmentation of labour be given?
- start on a low dose (1-4mU/min)
- doubled/increased every 30min to achieve optimal contractions (3-4 every 10min, each lasting 40-60s)
What monitoring must be used when giving synthetic oxytocin for augmentation or induction of labour?
continuous CTG monitoring
What must be used to deliver synthetic oxytocin for augmentation or induction of labour and why?
infsuion pumps to carefully control amount given, avoid risk of uterine hyperstimulation; sensitivity of myometrium to oxytocin increases during labour and may be necessary to reduce rate of infusion as labour advances
What are 3 benefits of the use of oxytocin to induce labour?
- reduce length of labour
- reduce operative births due to dystocia
- no major impact on neonatal outcomes
What are 7 risks and complications of induction of labour?
- Prematurity
- Cord prolapse with rupture of membranes if presenting part is not engaged
- Side effects of pharmacological agents
- Prostaglandins rarely cause non-selective stimulation of other smooth muscle leading to adverse effects
- CS due to failed induction
- Atonic post-partum haemorrhage
- Intrauterine infection with prolonged induction
What are 2 types of prematurity that may be caused by induction of labour?
- Iatrogenic e.g. if severe pre-eclampsia
- Unintention e.g. failure to correctly assess gestational age
What are 4 possible side effects of pharmacological agents used for induction of labour?
- pain or discomfort
- uterine hyperstimulation
- fetal distress
- uterine rupture - rare but increased in grand multipara or a scarred uterus
5.
What are 4 possible rare non-selective effects of prostaglandins at other smooth muscle sites that may be side effects of induction of labour?
- Nausea and vomiting
- Diarrhoea
- Bronchoconstriction (caution in asthmatics)
- Maternal pyrexia may result due to effect on thermoregulation in the hypothalamus
What blood test should you perform after oxytocin administration if it has been used for >12 hours and why?
U+Es: has the propoerties of ADH so may rarely cause dilutational hyponatraemia
What should you counsel a woman if she does not deliver after a course of prostaglandin?
don’t consider as failed induction but counsel to have deferred induction in a few days using same or different method
What are 4 special circumstances to consider in induction of labour?
- Prelabour rupture of membranes
- Stabilising induction
- Grand multipara (para 5 or more)
- Induction of intrauterine death at term
What can prostaglandins be used with for IOL if cervix is unfavourable following prelabour rupture of membranes?
prostaglandins may be used before starting syntocinon for IOL
What is a stabilising induction?
carried out when presenting part is not engaged or when there is an unstable lie, to avoid the risk of cord prolapse
What are the 3 steps in a stabilising induction?
- Head is stabilised by an assistant holding it suprapubically and if possible by pushing head into the pelvic brim
- Amniotomy performed after excluding cord presentation
- once cord prolapse excluded, oxytocin infusion started
Under what circumstances is a stabilising induction usually performed?
in delviery unit with theatre and team available should emergency of cord prolapse occur
good to have epidural that could be topped up sufficiently to allow emergency CS
What is the definition of grand multipara?
parity of 5 or more
Why should caution be exercise in IOL in grand multipara?
risk of uterine rupture is higher - prostaglandin gel should only be used in exceptional circumstances
What method of induction of labour should caution be exercised with in grand multipara?
prostaglandin gel - only use in exceptional circumstances
What are the usual 3 steps of induction of labour in grand multipara?
- onset of labour awaited for 4h after ARM
- in absence of contractions, oxytocin infusion can be started, titrated to get 3-4 every 10 min, each lasting >40s
- once contractions established, should be possible to stop oxytocin as most will continue to labour normally
What must be excluded before starting oxytocin in grand multipara?
malpresentation (obstructed labour)
What is the recommended method of induction of labour for intrauterine death at term?
misoprostol 25micrograms every 2-4 hours; not available in UK so 200mcg tablets can be dissolved in 40ml water and 5ml administered
(uniformity of strength not guaranteed but safer than administering higher dose)
What is there a risk of with induction of labour if there’s a previous C-section?
risk of scar dehiscence with previous uterine surgery
What is the risk of scar dehiscence with previous uterine surgery in 1. spontaneous labour 2. use of oxytocin 3. with prostaglandins?
- 5 in 1000
- 8 in 1000
- 24 in 1000
What are 3 things to ensure when performing induction of labour in a woman who’s had a previous C-section?
- Counselled regarding risk of scar dehiscence
- Continuous CTG monitoring throughout whole induction process when contractions present
- Facilities available for immediate C-section should there be scar rupture and fetal bradycardia
