Medications used in labour Flashcards
What is the Bishop’s score used for?
What does it indicate??
To clinically assess the cervix. The higher the score, the more progressive change there is in the cervix and indicates that induction is likely to be successful and indicates when an amniotomy is likely to be possible
What are the absolute contraindications of labour?
» Abnormal lie
» Known pelvic obstruction such as tumour or large ovarian cyst
» Placenta praevia
» Fetal distress
What are the relative contraindications of labour?
» Previous caesarean section = Increased risk of rupture
» Asthma (prostaglandins (including PGE2 analogues) can cause respiratory smooth muscle contraction).
How can prostaglandins induce labour?
Prostaglandin analogues encourage cervical dilatation and effacement –
they ripen the cervix and so can be used for induction of labour
Examples of prostaglandin analogues (E2)?
Dinoprostone - Propess® / Prostin E2® = Prostaglandin E2 analogues
Examples of prostaglandin analogues (E1)?
Misoprostol (Mysodelle ®) = synthetic analogue of Prostaglandin E1
What are the risk of prostaglandins in labour induction?
May lead to contractions, occasionally can lead to severe contractions / hypertonic uterus, nausea and vomiting, bowel upset, pyrexia, hypotension
How can oxytocin induce labour?
Synthetic Oxytocin (Syntocinon®) – initiates uterine contractions by attaching to uterine oxytocin receptors ; increases the frequency and force of contractions
What are prostaglandins derived from?
Eicosanoids derived from arachidonic acid
Where is oxytocin derived from?
Oxytocin is produced physiologically by the paraventricular nuclei and secreted by the posterior pituitary gland
How is oxytocin administered in labour?
IV administration
What is oxytocin?
Oxytocin is a cyclic nonapeptide
Why do women need CTG monitoring if an oxytocin infusion is administered?
There is a risk of uterine hypertonicity
What is the risk of using oxytocin in the induction of labour?
Can lead to hypotension and hyponatraemia – women usually have IV fluids alongside oxytocin infusion – need to be cautious with use and must monitor fluid balance
When is oxytocin usually administered when inducing labour?
Often used following prostaglandin treatment, once amniotomy performed for induction of labour
When is augmentation of labour required?
Augmentation of labour is required when contractions reduce in frequency or strength in active labour even after spontaneous onset of labour.
What is used to augment labour, if indicated?
Oxytocin
What does active management of the 3rd stage of labour involve?
Active management of the 3rd stage involves:
1. Early clamping and cutting of the umbilical cord (now routine practice is to allow 2-5 minutes of delayed cord clamping for all women unless contraindicated)
- Use of uterotonic medications (pharmacological management)
- Delivery of the placenta by controlled cord traction
Which medication are used within active management of the 3rd stage of labour?
1) Syntometrine:
- Combination of oxytoxin and ergometrine
- Given as an IM injection
2) Synthetic oxytocin:
- Given as IM injection or slow IV injection (5 IU)
Pharmacological management of post partum haemorrhage (PPH)?
1) Oxytocin:
- IV injection (5IU)
- IV infusion (30 IU in 500ml normal saline at a rate of 125ml/hr)
2) Syntometrine ® or ergometrine alone:
- IM 500mg
3) Carboprost (Hemabate®)
- Is a Prostaglandin F2α
- Given as IM injection (250 micrograms) at 15 minute intervals (to maximum of 8 doses (2mg)
4) Misoprostol
- A prostaglandin; sometimes given PR to help treat PPH. This is an unlicensed medication for the treatment of PPH
5) Tranexamic acid
- Is an antifibrinolytic medication therefore can be used to try to reduce the bleeding in
ongoing PPH if other pharmacological methods are not working
What should be given in threatened preterm labour, why?
Steroids should be administered to help improve neonatal outcomes
Steroid administration is thought to improve fetal lung development and improve other neonatal outcomes in preterm babies
Which drugs should be given in threatened preterm labour, why?
Betamethasone or dexamethasone is given to the woman by IM injection (2 x 12mg doses given 24 hours apart).