Labour Induction Flashcards
What is labour induction?
It is the stimulation of uterine contractions during pregnancy, before labour begins on its own, to achieve a vaginal birth
When is labour induction generally indicated?
When it is thought that delivering the baby will be safer for the baby and the mother, than for the baby to remain in utero
What are the four specific indications of labour induction?
Prolonged Gestation
Prelabour Rupture of Membranes
Maternal Health Problems
Fetal Health Problems
At what gestation do we offer labour induction?
40 - 42 weeks
What are the two risks of prolonged gestation, hence why we offer labour induction?
Fetal compromise
Stillbirth
What is prelabour rupture of membranes?
It is the term used when a patient’s waters have broken prior to labour starting
What four maternal health problems indicate labour induction?
Hypertension
Pre-eclampsia
Diabetes
Obstetric cholestasis
What three fetal health problems indicate labour induction?
Fetal Growth Restriction
Oligohydramnios
Intrauterine Fetal Death
What is fetal growth restriction? At what estimated weight percentile?
It is a condition in which a fetus is smaller than expected for its gestational age
< 10th percentile
What is oligohydraminos?
It refers to amniotic fluid volume that is less than expected for the gestational age
What is intrauterine fetal death?
It is when a fetus dies inside the womb before birth
What are the two general categories of labour induction contraindications?
Absolute
Relative
What are absolute contraindications of labour induction?
They define events that could cause a life-threatening situation, and therefore induction is essential
What are the seven absolute contraindications of labour induction?
Cephalopelvic Disproportion
Vasa Praevia
Placenta Praevia
Prolapsed Umbilical Cord
Active Primary Genital Herpes
Foetal Distress
Oblique Lie
What are relative contraindications of labour induction?
They define events that should be approached with caution, however, are frequently performed
What are the three relative contraindications of labour induction?
Breech Presentation
Maternal Asthma
Previous C-Section
What are the five mechanisms of labour induction?
Membrane Sweep
Vaginal Prostaglandins
Cervical Ripening Balloon (CRB)
Amniotomy
Prostaglandin Analogues
What is a membrane sweep?
It is performed by inserting a gloved finger through the cervix and rotating it against the fetal membranes
How does a membrane sweep induce labour?
This separates the chorionic membrane from the decidua
The separation releases natural prostaglandins in an attempt to initiate labour
When are membrane sweep mechanisms recommended?
In patients who have a prolonged gestation date between 40 - 42 weeks
It is not considered a full method of inducing labour and is more of an assistance before full induction
By performing it, the likelihood of spontaneous delivery increases, reducing the need for a formal induction
What is another name for vaginal prostaglandins E2?
Dinoprostone
What is prostaglandins?
A hormone
What is prostaglandins?
A hormone
What are the two functions of prostaglandins?
It ripens the cervix
It contracts the smooth muscle within the uterus
When is vaginal prostaglandins recommended?
It is the preferred management option when cervical ripening has not yet occurred, usually indicated by a Bishop’s score less than six
What is the cervical ripening balloon procedure?
It involves the insertion of a silicone balloon into the cervix to prepare it for labour by ripening it
When is cervical ripening balloon recommended?
This induction method is only selected if cervical ripening has not yet occurred, usually indicated by a Bishop’s score less than eight
It is used as an alternative where vaginal prostaglandins is not preferred
In which three circumstances is vaginal prostaglandins not preferred to induce labour?
A previous c-section
When prostaglandins has failed
In multiparous women > 3
What is amniotomy?
It is where the membranes are ruptured artificially using an instrument called an amniohook
This process releases prostaglandins
What do we administer following amniotomy? Why?
An infusion of artificial I.V oxytocin
This is used to achieve adequate contractions
What contraction rate should we aim during labour induction?
4 contractions every 10 minutes
When is amniotomy recommended to induce labour?
When cervical ripening has occurred
Name two prostaglandin analogues
Mifepristone
Misoprostol
When are prostaglandin analogues recommended to induce labour?
When intrauterine fetal death has occurred
In what two ways do we monitor labour induction?
Bishop score
Cardiotocography
What is the bishop score?
It is a pre-labour scoring system used to predict whether induction of labour will be required
It can also be measured during induction of labour to monitor the progress
What are the five criteria of the bishop score?
Dilatation (cm)
Cervix length (cm)
Position
Consistency
Fetal Station
What does a bishops score > 8 indicate?
A successful induction of labour
What does a bishops score < 8 indicate?
A score less than eight suggests cervical ripening may be required to prepare the cervix before induction
What does a bishops score < 5 indicate?
Labour induction
What does a bishops score < 5 indicate?
Labour induction
How is cardiotocography (CTG) used to monitor labour induction?
It is used to assess the fetal heart rate and uterine contractions
It is also used following an oxytocin infusion, to monitor the stimulated contractions
What are the three complications of labour induction?
Induction Failure
Uterine Hyperstimulation
Cord Prolapse
How do we manage induction failure?
We can offer these patients a further cycle of prostaglandins or a c-section
What is uterine hyperstimulation?
It occurs when the contraction of the uterus is prolonged and frequent
What labour induction mechanism is associated with uterine hyperstimulation?
Prostaglandins
What are the three complications of uterine hyperstimulation?
Foetal Distress
C-Section
Uterine Rupture
How do we manage uterine hyperstimulation?
We administer tocolytic agents, such as terbutaline
What labour induction mechanism is associated with cord prolapse?
Amniotomy, particularly if the presentation of the fetal head is high
