Induction and Augmentation of Labour Flashcards
What proportion of women are commonly induced and what are some common reasons why a woman might be induced?
24%
PROLONGED PREGNANCY (beyond 41 weeks) - if you allow pregnancy to continue there is a risk of placental insufficiency, fetal hypoxia/distress and meconium staining
IUGR (baby will probably grow better outside the uterus)
PPROM (pre-term pre-labour rupture of membranes) Induction at 34-35w due to risk of chorioamnionitis
APH
DIABETES - women with maternal DM or GDM are induced at 38 weeks due to increased chance of placental insufficiency and increased size of babies
POOR OBSTETRIC HISTORY
INTRAUTERINE DEATH
MATERNAL HYPERTENSION
What are some contraindications for induction?
ABSOLUTE
ACUTE FETAL DISTRESS - labour will lead to further distress for the baby and so CS is usually best way
UNSTABLE LIE - transverse or breech lies will not be delivered vaginally and so induction shouldn’t be done - CS
PLACENTA PRAEVIA - vaginal delivery not possible
PELVIC OBSTRUCTION
RELATIVE PREVIOUS CS BREECH - can be delivered vaginally with experiences obstetrician PREMATURITY HIGH PARITY
There are lots of different ways of inducing a woman, what is the first that should be tried?
Before formal induction should try MEMBRANE SWEEP (STRETCH AND SWEEP)
When should a stretch and sweep be trialed?
Between 40-41 weeks in nulliparous women and 41 weeks in multiparous women
How do stretch and sweeps work?
Separating the membranes from the cervix releases prostaglandins - it is hoped that this PG surge is enough to start labour
Women can be sent home to await the beginning of labour after a short period of observation
How do we decide which form of induction is most appropriate?
Will depend on the reason the woman is being induces as well as her BISHOP’S SCORE
What factors are included in the Bishop’s score and what is it out of?
Dilation (0-3) Length of cervix (0-3) Station (0-3) Consistency (0-2) Position (0-2)
Out of 13 (13 is ready to deliver)
<6/13 - induction is unlikely to be successful
>8/13 - induction likely to be successful
After the stretch and sweep has been trialed what, more formal, methods can we use for induction?
PRIMING OF THE CERVIX WITH EXOGENOUS PROSTAGLANDINS
This is usually done by inserting a Prostaglandin Gel (known as Prostin) into the posterior fornix of the cervix
More than one dose may be required but wait for a reaction first
How is prostin given?
As gel into the posterior fornix (cervix should be at least partially dilated). The following preparation are commonly used: PROSTIN GEL (Dinoprostone - PGE2) - 1mg or 2mg dose release over 6 hours PROPESS: (Dinoprostone - PGE2) 10mg released over 24h
How do we decide how much prostin to give?
Depends on woman’s parity
NORMALLY:
2mg doses are given 6hours apart (women sent home in mean time) - may need 2 or 3
MULTIP WOMEN may only need 1mg doses and might only need 1 (Obstetrician guidance)
What do we try after prostin gel?
IF THE CERVIX IS ALREADY FAVOURABLE
Artificial rupture of membranes
Oxytocin therapy
How do artificial rupture of membranes (ARM) work? Why is it a good method?
Uterine decompression and local PG release
It also allows for the assessment of the liquor (is it meconium stained)
What are the risks with ARM? How are these minimised?
Risk of cord prolapse - should make sure the head is well engaged with the cervix before rupture and should also make assessment with vaginal examination after amniotomy has been performed.
What method can be used for induction after ARM has been tried?
SITUATION: cervix is favourable, ARM been tried
OXYTOCIN / SYNTOCINON INFUSION (syntocinon is synthetic oxytocin)
RISK of hypertonic uterus and fetal distress CTG MONITORING IS REQUIRED THROUGHOUT LABOUR
This can also be used to augment labour
What are some potential complications of induction?
Fetal distress (CTG monitoring throughout)
Precipitate delivery (unusually rapid labour)
Operative Labour (forceps)
Uterine hypertonia - increased risk of rupture
Amniotic fluid embolus
Systemic effects
