Delivery Flashcards
What is induction of labour?
The process of starting labour artificially.
What are the indications for induction of labour?
Prolonged gestation Premature rupture of membranes Maternal health problems Foetal growth restriction Intrauterine foetal death
When should IOL be offered for prolonged gestation and why?
Uncomplicated pregnancies should be offered IOL between 40+0 to 40+14 weeks.
The aim is to avoid the risks of foetal compromise and still birth associated with prolonged gestation (thought to be due to secondary placental aging).
What happens when a patient declines induction of labour in prolonged gestation for an uncomplicated pregnancy?
The frequency of monitoring from 42 weeks onwards should be increased.
When should IOL be offered for premature rupture of membranes? What can be done alternatively?
Over 37 weeks gestation.
Alternatively CN offer expectant management for a maximum of 24 hours (any longer and risk of ascending infection - chorioamnionitis). 84% of women will spontaneously go into labour within the first 24 hours.
When should IOL be offered for preterm premature rupture of membranes?
Under 34 weeks - delay IOL unless obstetric factors indicate otherwise e.g. foetal distress
Over 34 weeks - the timing of IOL depends on risks vs benefits of delaying pregnancy further e.g. increased risk of infection
What are the maternal health problems that can cause an induction of labour?
Hypertension
Pre-eclampsia
Diabetes
Obstetric cholestasis
The decision to induce will depend on the health of the mother and the foetus
What is the aim of induction of labour in foetal growth restriction?
The aim is to deliver prior to foetal compromise.
Foetal growth restriction is the second most common indicator for induction of labour.
What are the absolute contraindications for IOL? (Generally the same as for vaginal delivery)
Cephalic disproportion Major placenta praevia Vasa praevia Cord prolapse Transverse lie Acute primary genital herpes Previous classical Caesarean section
What are the relative contraindications for IOL? (Similar to those for vaginal delivery)
Breech presentation
Triplet or higher order pregnancy
2+ previous low transverse C sections
Can a woman who has had a previous C section be offered IOL?
Can once assessed by a consultant and they are happy for it to proceed.
The mother should however be aware of the increased risk of emergency C section and uterine rupture.
What are the methods of induction of labour?
Vaginal prostaglandins (mainstay)
Amniotomy
Membrane sweep
Describe how vaginal prostaglandins act in the induction of labour.
This is the preferred primary method.
Prepare the cervix by ripening it and also has a role in the contraction of smooth muscle of the uterus.
How can vaginal prostaglandins be administered for the induction of labour?
Tablet/gel regimen (1 cycle = 1st dose + 2nd dose if labour has not started 6 hours later) Pessaries regimen (1 cycle = 1 dose over 24 hours) - recommended one cycle in 24 hours (IOL can sometimes take multiple days)
Describe the process of amniotomy.
The membranes are ruptured artificially using and amnihook. This releases prostaglandins. Only performed when the cervix is deemed ripe.
Often, an infusion of artificial oxytocin (syntocinon) will be given alongside an amniotomy, acts to increase the strength and frequency of contractions. The aim is to start low and titrate upwards until there are 4 contractions every 10 minutes.
When is amniotomy indicated for induction of labour?
Only use when vaginal prostaglandins are contraindicated e.g. ugh risk of uterine hyperstimulation
When is the membrane sweep offered?
At 40-41 weeks to nulliparous women and 41 weeks to multiparous women.
It is classified as an adjunct of IOL. Performing it increases the likelihood o spontaneous delivery, reducing the need for formal induction.
Describe the procedure of a membrane sweep.
Gloved finger inserted through the cervix and rotated against the foetal membranes.
Aims to separate the chorionic membrane from the decidua. The separation helps to release natural prostaglandins in an attempt to start labour.
What is the bishop score used for?
It is an assessment of cervical ripeness based on measurements taken during vaginal examination.
What is the bishop score used?
Checked prior to induction and during induction to assess progress (6 hours post-tablet/gel, 24 hours post-pessary)
What does a bishop score of 7 or more suggest?
Suggests that the cervix is ripe/favourable (high change of response to interventions made to induce labour)
What does a bishop score of less than 4 suggest?
Labour unlikely to progress naturally and prostaglandin tablet/gel/pessary will be required.
What happens if there is failure of the cervix to ripen despite use of prostaglandins?
C section may be necessary
When is CTG used in the induction of labour?
Prior to IOL a reassuring foetal HR must be confirmed.
After initiation when contractions begin continuous CTG monitoring is required until a normal rate confirmed (subsequently assess using intermittent auscultation).
If oxytocin infusion started - continuous CTG throughout labour.
What are the complications of induction of labour?
Failure of induction (offer further PG/C section)
Uterine hyperstimulation
Cord prolapse (at time of amniotomy id presentation of the foetal head is high)
Infection (rescued using a pessary as fewer vaginal examinations required)
Pain (more painful than spontaneous labour - epidural may be required)
Increased rate of further intervention (emergency C sections and instrumental deliveries)
Uterine rupture (rare)
What is uterine hyperstimulation? How is it managed?
Contractions last too long or are too frequent
Leads to foetal distress
Managed using tocolytic agents (anti-contraction) such as terbutaline.
What is an operative vagina delivery?
The use of an instrument to aid delivery of the foetus.
What are the 2 main instrument types used in operative deliveries? How do you decide which one to chose?
The ventouse
The forceps
Choice is operator dependent. Forceps have a lower risk of foetal complications, but a higher risk of maternal complications.
When should operative delivery be stopped?
If after 3 contractions and pulls with any instrument and there is no reasonable progress
What is a ventouse?
An instrument that attaches a cup to the foetal head via vacuum.
What are the 2 most common types of ventouse?
An electric pump attached to a silastic cup (for occipito-anterior) or attached to a metal cup with the tubing attached to the side of the cup as opposed to the middle (for occipito-posterior)
Kiwi (handheld disposable device) - an omni cup which can be used for all foetal positions and rotational deliveries.
How is a ventouse used?
Cup applied with its centre over the flexion pint on the foetal skull (midline, 3cm anterior to the posterior fontanelle)
During uterine contractions, traction is applied perpendicular to the cup.
What are ventouse deliveries associated with?
Lower success rate Fewer maternal perineal injuries Less pain More cephallohaematoma More subgaleal haematoma More foetal retinal haemorrhage
What are forceps?
Double-bladed instruments
What are the different types of forceps?
Rhodes/Neville-Barnes/Simpsons - C section
Wrigley’s - C section
Kielland’s - rotational deliveries
How are forceps used in instrumental deliveries?
Blades introduced to the pelvis taking care not to cause trauma to maternal tissue and applied around the sides of the foetal head with the blades locked together.
Gentle traction is then applied during uterine contractions following the J shape of the maternal pelvis.
What are the advantages and disadvantages of the use of forceps in instrumental deliveries?
Higher rate of 3rd and 4th degree tears
Less often used to rotate.
Doesn’t require maternal effort.
What are the most common maternal indications for an operative vaginal delivery?
Inadequate progress
Maternal exhaustion
Maternal medical conditions that limit active pushing/prolonged extertion
Define inadequate progress in a nulliparous woman.
As a general rule, delivery is expected after 2 hours of active pushing
If no urge to push felt at 2nd stage (common with regional anaesthesia), an hour can be allowed for foetal descent prior to active pushing.
Define inadequate progress in a multiparous woman.
Delivery within an hour of active pushing
+ an hour prior if needed prior to active pushing for descent
Which maternal conditions may limit active pushing/prolonged exertion?
Intracranial pathologies
Congenital heart disease
Severe HTN
What are the foetal indications for operative vaginal delivery?
Suspected foetal compromise in the 2nd stage of labour
Clinical concerns e.g. significant anterpartum haemorrhage
How is foetal compromise diagnosed?
Decelerations on CTG
Abnormal foetal blood sample
What are some of the absolute contraindications for an operative vaginal delivery?
Unengaged foetal head in singleton pregnancies
Incompletely dilated cervix in Singleton pregnancies
True cephalo-pelvic disproportion (head to large to pass down pelvis)
Breech/face/most bro presentations
Preterm gestation (<34 weeks) for ventouse
High likelihood of any foetal coagulation disorder for ventouse
What are the relative contraindications for operative vaginal delivery?
Severe non-reassurance foetal status