Indications, methods and complications Flashcards
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What is IOL?
Labour that is induced artificially
How is it different from Augmentation?
In augmentation, already established contractions are strengthened. IOL involves inducing labour, not building on pre-existing work
Why is IOL performed?
Indicated in any situation where allowing the foetus/mother to a risk greater than that of induction (in reality, this quantification is rarely simple)
What percentage of UK labours are artificially induced?
20%
What are the reasons for the majority (75%) of IOLs?
HNT
Prolonged pregnancy (after 41 w, inc risk of stillbirth)
Pre-eclampsia
Rhesus disease
What are less common (but still relevant) reasons for induction?
Diabetes (and other maternal medicine complications) Previous stillbirth Abruption Foetal death in utero Placental insufficiency IUGR Foetal congenital abnormalities Pre-labour prolonged rupture of membranes
What are contraindications?
Malpresentation (inc breech) Foetal distress Placenta praevia Cord presentation Vasa praevia Pelvic tumour (e.g. cervical fibroid)
What can be done to avoid IOL with medication?
Membrane sweep
There is no evidence for sex, castor oil, enemas, acupuncture, homeopathy, herbal supplements or hot baths
What are the risks of IOL?
Prolonged labour duration More likely to need regional anaesthesia (and an operative delivery) Failure to establish labour (15%) (NOT assoc with inc LSCS risk) Postpartum haemorrhage Intra and postpartum infection Uterine hyperstimulation Uterine rupture Umbilical cord prolapse
What are the risks of delay labour beyond 40+12?
Increased perinatal mortality
Increased risk of intervention (LSCS)
What would a midwife typically do in a woman who has consented to IOL?
Confirm gestation
Palpate foetal lie, position and engagement
Perform CTG
Vaginal exam to assess cervical favourability
What is Naegle’s rule?
LMP -3mo +7d
When is the EDD typically calculated?
At dating scan (around 12w) from crown rump length
How is the state of the cervix assessed?
Bishop’s score
The risk of what increases if primips are induced with a Bishop’s <3?
Prolonged labour
Foetal distress
LSCS
What is a favourable Bishop’s?
> 5
What if Bishop’s >7?
Induction via ARM (avoids use of prostaglandins)
What are the methods of IOL?
Prostaglandins (ripen cervix, enable amniotomy)
Amniotomy
Syntocinon infusion
Mechanical cervical dilators
What forms of prostaglandin are available?
Pessary (Prostin) 10mg/24hr
Gel (Prostin gel) 1-3mg/6hrly
Slow-release preparation (Propess)
When giving prostaglandins, what else should be performed?
CTG (pre PG use and 30mins after insertion
How do prostaglandins induce labour?
Stimulate uterine contractions or precipitate labour
If membranes cannot be ruptured 48hrs after PG use, what can be done?
Try IOL again
LSCS
What is amniotomy?
Rupture of membranes, spontaneous or artificial (SRM/ARM)
What is the woman at risk of from amniotomy?
Cord prolapse (MEDICAL EMERGENCY - compression/vasospasm that causes foetal asphyxia)
How is cord prolapse managed?
Decompress cord by manual elevation of baby head and putting mother in prone knee-chest position or filling maternal bladder with saline
Unless woman is fully dilated, LSCS needs to be performed
What should be done to the foetus once amniotomy has occurred (SRM or ARM)?
Intrapartum CTG
Allow woman to mobilise for 2-4hrs to induce contractions (if liquor clear)
What if woman is not experiencing contractions after amniotomy?
Oxytocin 1-4 milliunits/minute, increasing every 30 mins until woman experiencing 4 contractions every 10 mins (typically 4-10MU/min)
When should oxytocin/IOL be stopped?
If CTG shows foetal distress or uterine hyperstimulation (>5 contractions/10 mins with foetal compromise)
Should women with previous caesarean sections have IOL?
Consult with senior (inc risk of scar rupture with prostaglandins and oxytocin)
What alternative medication can be used to induce labour (and what is the condition for its use)?
Misoprostol
PO/PV has lower chance of hyperstimulation
Only use for IOL after intrauterine death
What analgesia options are available for women in labour?
Non-pharmacological -Hypnotherapy/relaxation techniques -Aromatherapy -TENS -Water Pharmacological -Simple analgesia -Opioids (include PCA for IUD or where RA is contraindicated); short-term neonatal effects if delivery within 2 hrs of pethidine -Entonox (gas and air) -Regional anaesthetic (RA); assoc with increased risk of instrumental delivery
How is the dose of syntocinon (oxytocin) titrated?
Titrated against the rate of maternal contractions
What are the pathological causes of abnormal CTGs?
Hyperstimulation
Advancing labour
(Foetal hypoxia main concern)
How to manage abnormal CTG in IOL?
Assess progress using vaginal exam
Turn down syntocinon to reduce frequency of contractions
What are the next steps if contraction rate is slowed but CTG still abnormal?
Without foetal blood sample, difficult to ascertain cause.
50% of abnormal CTGs assoc with foetal compromise and so require urgent delivery
What is a normal finding on foetal blood sampling?
> 7.25 (would need repeating in 1 hr if CTG remained abnormal)
If 7.20-7.25, repeat in 30 mins
If <7.20 foetus at substantial risk of hypoxia and needs urgent delivery
If FBS is 7.32, cervix fully dilated and foetus in OA, what is the best mechanism for delivery?
Instrumental delivery (no point waiting to repeat FBS as foetus easily deliverable)
What should be performed once baby is delivered?
Cord gas analysis
What instrument can be used to rupture membranes artificially?
Amnihook
When is the best time to perform IOL?
38w
