IOL and OVD Flashcards
What is Induction of Labour (IOL)?
- Process of starting labour artificially, most women go into labour spontaneously by 42 weeks gestations, some will require an induction.
- When it is thought baby is safer being delivered rather than remaining in utero, or for reasons concerning mother’s health.
- Prior to induction - reassuring foetal heart rate must be confirmed by CTG.
- After initiation of labour, when contractions begin, monitor FHR using continuous CTG until normal heart rate confirmed - subsequently assess with intermittent auscultation.
- IF oxytocin infusion started - monitor using continuous CTG throughout labour.
Indications for IOL?
1) Prolonged gestation - Women with uncomplicated pregnancies should be offered IOL from 40-42wks - due to risks of foetal compromise and stilbirth associated with prolonged gestation (secondary to placental ageing). If woman declines - increasing monitoring from 42 weeks.
2) Premature rupture of membranes - For premature rupture of membranes >37 weeks offer IOL or offer expectant management for 24 hours. 84% will spontaneously go into labour within 24 hours. <34 weeks - delay IOL unless foetal distress etc. >34 weeks - depends on risk vs benefits of delaying pregnancy.
3) Maternal Health Problems - Depends on health of mother and foetus, consider if pre-eclampsia, HT, gestational diabetes and obstetric cholestasis.
4) Foetal Growth Restriction - Foetal growth restriction second most common indication for induction of labour.
5) Intrauterine Foetal Death - IOL should be offered if other is physically well with intact membranes.
Contraindications for IOL?
- Same as for vaginal delivery - divided into absolute contraindications and relative contraindications.
- ABSOLUTE CI:
1) Cephalopelvic disproportion
2) Placenta praevia
3) Vasa praevia
4) Cord prolapse
5) Transverse lie
6) Active primary genital herpes
7) Previous classical C-Section - RELATIVE CI:
1) Breech presentation
2) Triplet or higher order pregnancy
3) Two or more previous low-level transverse C-sections
If previous C-sections - IOL can be offered safely after she has been seen and assed by a consultant (who is happy for IOL to proceed) - mother should be aware of increased risk of emergency C-section and uterine rupture.
Three main methods of induction? - Vaginal Prostaglandins
1) Vaginal Prostaglandins - - Forms mainstay of labour, preferred method
- Tablet 1 cycle = 1 dose + 2nd if labour has not started in 6 hours, gel (same as tablet) or controlled-release pessary (1 cycle = 1 dose over 24hrs)
- Ripens cervix and has role in smooth muscle contraction in uterus.
- FIRST LINE
Amniotomy - 2nd line IOL?
2nd LINE: Amniotomy - Membranes ruptured artificial by amnihook - as with a membrane sweep this process releases prostaglandins to initiate labour - only when cervix deemeed ‘ripe’. Artificial oxytocin (syntocinon) infusion often given alongside amniotomy to increase strength and frequency of contractions (start low and titrate up until 4 contractions every 10 minutes). ONLY USED IF PROSTAGLANDINS ARE CONTRAINDICATED ( e.g.uterine hyperstimulation)
Membrane Sweep - IOL?
Membrane sweep - offered at 40-41 weeks to nulliparous and 42wks for multiparous.
- It is an adjunct of IOL - increases likelihood of spontaneous delivery reducing need for formal induction.
- Inset gloved finger through cervix and rotating it against foetal membranes - helps release natural prostaglandins in an attempt to kick-start labour.
What is the Bishop’s score?
- Bishop score is an assessment of ‘cervical ripeness’ based on measurements taken during vaginal examination.
- Checked prior to induction - during induction to assess progress (6 hours post tablet/gel, 24 hours post pessary).
- Score of >7 suggest cervix is ripe or favourable - induction is possible
- Score of <4 - suggests labour unlikely to progress naturally and prostaglandin tablet/gel/pessary will be required
- FAILURE OF CERVIX TO RIPEN DESPITE USE OF PROSTAGLANDINS - C-SECTION considered.
Bishop’s table?
- Dilation, length, station (relative to ischial spines), consistency and position considered.
- Score of >7 - ripe cervix, <4 unlikely to progress naturally.
DILATION: <1 (0), 1-2 (1), 2-4 (2), >4 (3)
LENGTH: >4 (0), 2-4 (1), 1-2 (2), <1 (3)
STATION: -3 (0), -2 (1), -1-0 (2), 1-2 (3)
CONSISTENCY: Firm (0), Average (1), Soft (2)
POSITION: Posterior (1), mid/anterior (1)
Complications of IOL?
1) Failure of induction - further cycle of prostaglandins or C-section.
2) Uterine hyperstimulation - contractions last too long/too frequent
3) Cord prolapse - occur any time of amniotomy particularly if presentation of head too high
4) Infection - risk is reduced by using pessary vs tablet/gel - few vaginal examinations are required to check progress.
5) Pain - IOL often more painful than spontaneous labour - epidural required often.
6) More likely to require further intervention (emergency c-section/instrumental devices)
7) Uterine rupture (rare)
What is an operative vaginal delivery (OVD)? Types?
- Use of an instrument to aid delivery.
- TWO MAIN TYPES - VENTOUSE AND FORCEPS
- First instrument used is most likely to succeed - choose is operator dependant - forceps tend to have lower risk of foetal complications + higher risk of maternal complications.
- ABANDON ATTEMPT after THREE CONTRACTIONS AND PULLS WITH ANY INSTRUMENT - if no reasonable progress.
Ventouse info:
- Attached cup to foetal head via vacuum - electrical pump attached to Silastic cup (occipital-anterior only), hand-held disposable device - KIWI (omni cup used for all foetal positions and rotational deliveries).
- Bird cup also can be used with electrical pump and suitable for occipital-posterior positions.
- Cup applied with centre over FLEXION POINT on foetal skull - during uterine contractions traction applied perpendicular to cup.
Venthouse deliveries pros and cons:
- Lower success rates
- Less maternal perineal injuries
- Less pain
- More cephalhaematoma
- More foetal retinal haemorrhage
- More subgaleal haematoma
Forceps info:
- Double bladed instruments - include Rhodes, Neville Barnes, or Simpson’s - used for OA positions, Wigley’s used at C-section, Kielland’s used at rotational deliveries.
- Blades introduced into pelvis and applied around sides of foetal head - blades lock together and gentle traction is applied during uterine contractions.
Associated with - Higher rate of 3rd/4th degree tears, less often used to rotate, does not require maternal effort.
Maternal Indications of Operative Vaginal delivery?
- Should be based on entire clinical scenario of the second stage of labour.
- 2 questions - valid clinical indication to intervene? Is patient suitable for instrumental delivery?
Maternal indications:
1) Inadequate progress (after 2 hours in nulliparous and 1 hour in multiparous - with an hour for foetal descent if needed prior to active pushing)
2) Maternal exhaustion
3) Maternal medical conditions - active pushing/prolonged exertion should be limited - congenital hear conditions, inter cranial pathologies, severe hypertension.
Foetal indications for Operative Vaginal Delivery?
- Suspected foetal compromise in the second stage of labour - diagnosed by abnormal foetal blood sample/or abnormal CTG findings.
