Induction of Labour Flashcards
What is required for a pregnancy to continue?
- Cervix to remain closed and rigid
- Uterus to remain quiet/ not contracting
- Progesterone = prevents stimulation of oxytocin receptors in the uterus
What triggers labour?
- Hormones
- Ferguson’s Reflex
- Prostaglandins
How do hormones trigger labour?
- Release of oxytocin which stimulates contractions of uterus
- Decreased progesterone levels
How does the Ferguson’s reflex trigger labour?
- Pressure on the cervix from PP
- Surge of oxytocin
- Uterus contracts
How do prostaglandins trigger labour?
- Produced by the chorion and amnion
- Soften and ripen cervix by breaking bonds between cells
What is the difference between induction and augmentation?
Induction = the artificial initiation of labour Augmentation = progress of labour is enhanced
Give some possible reasons for the increased induction rates
- Increased BMI = increased GDM
- Increased mat age
- More co-mordbidities
- More RFM awareness
- Maternal request
Give some foetal reasons for induction of labour
- Large for dates/ IUGR
- Multiple pregnancy
- 3 x RFM
- Foetal death
What is not a foetal indication for IOL?
Macrosomia with no other issues
Give some maternal reasons for induction of labour
- OC
- Pre-eclampsia
- Post dates
- Diabetes
- Pre-labour rupture of membranes
- Maternal request
Give some other reasons for induction of labour
- IVF
- Placenta function
- Obstetric history (precipitate labour, previous IUD, infertility, prev. large baby)
What is the difference between a prolonged pregnancy and post-maturity?
Prolonged pregnancy = >40/40
Post-maturity = a particular clinical syndrome during a pathologically prolonged pregnancy (>42/40)
When should an induction ideally take place?
40+10 to 40+14
Why should an induction take place before 42/40?
Fewer perinatal deaths, CS and infant morbidities
What risks are associated with induction/augmentation?
- Hyperstimulation
- Failed induction
- Uterine rupture
- Increased need for CS
- PPH (NICE 2014)
What does hyperstimulation increase the risk of?
- Foetal hypoxia
- Uterine rupture
- PPH
What does fluid overload increase the risk of?
- Cardiac arrest
- Pulmonary oedema
What is the use of a prostin associated with?
- Higher rate of vaginal delivery within 24 hours
- Increase in maternal satisfaction
What are the normal doses for prostin and propess?
Prostin = 3mg gel (primip 2,1,1, multip 1,1,1) Propess = 10mg pessary
Describe the relationship between BISHOP score and the use of prostin/propess
>6 = prostin (should be given >6 hours before synto) <6 = propess (should be given >30 mins before synto)
What are the 4 other forms of prostaglandin?
Prostin tablet
Pessary
Controlled release pessary
Dilapan-S
What is the formula for prostaglandins?
PGE2
How does the Dilapan-S work?
It is a new cervical dilator that is places in the cervix and expands by osmosis
Describe the procedure of induction
- One cycle of controlled-release pessary (max. 1 dose, given over 24 hrs)
- One cycle of prostin tablet/gel, one dose followed by second dose after 6 hours if labour is not established (max 2 doses, 3rd dose given by doctor)
What is the procedure for PROM?
Give prostin and then synto after 6 hours
When are sweeps usually performed?
Primip = 40/40 and 41/40
Multip = 41/40
If booked for induction at 38/40, can do sweep at 37/40
What are the main risks of sweeps?
- Infection
- Rupturing membranes
What are the indications for ARM?
- Can be used for augmentation or IOL
- Usually done with a BISHOP score of >7
What is syntocinon aimed at achieving?
Contractions 4:0 lasting 40-90 seconds
What are the different concentrations of synto?
3iu in 50ml NaCl
30iu in 500ml NaCl
10iu in 500ml NaCl
How often should the concentration of synto be increased?
Every 30 mins
What are the benefits of using ARM and oxytocin together?
- Fewer women not delivered by 24 hrs
- Fewer women need instrumental deliveries
- Lead to more PPHs
What are some common side effects of prostin?
- Hyperstimulation
- Uterine rupture
- Gastric disturbances
- Headache
- Abdominal pain
What is the usual dose of oxytocin?
10iu/1ml ampoule
What are some common side effects of oxytocin?
- Hyperstimulation
- Uterine rupture
- Anti-diuretic
- Nausea and vomiting
- Tachycardia
What is mifepristone used for and what is the usual dose?
- Ripens cervix for ToP
- 200mg 36-48 hrs before procedure
What are some common side effects of mifepristone?
- Abdominal cramps
- D+V
- Infection
- Vaginal haemorrhage
What are some uncommon side effects of mifepristone?
- Hypotension
- Chills/dizziness/malaise
- Toxic shock syndrome
What is misoprostol used for and what is the usual dose?
- Given after mifepristone OR given PR for PPH
- 400mcg 24-48 hrs after mifepristone
What are some common side effects of misoprostol?
- Constipation
- D+V
- Dizziness
- GI discomfort
What are some uncommon side effects of misoprostol?
- Fever
- Haemorrhage
What procedure is used for an intrauterine death?
- 200mg mifepristone
- 36-48 hours later = 800mcg misoprostol given PV and 400mg PO (max. 5 doses)
What drug is not licensed for IOL in the UK?
Misoprostol
Give 8 ways of ‘bringing on’ labour
- Curry (bowel/uterine irritant)
- Sex (orgasm releases oxytocin)
- Raspberry leaf tea (makes uterus work well)
- Dates and pineapple
- Nipple stimulation (oxytocin)
- Castor oil (bowel irritant)
- Primrose oil
- Acupuncture
