RANZCOG - instrumental vaginal delivery Flashcards
What is the incidence of vacuum and forceps assisted vaginal births in Australia and NZ?
10%
What are 3 non operative interventions that may reduce the need for instrumental delivery?
- continuous midwifery support during labour
- upright or lateral positions in 2nd stage
- use of oxytocinon
List 3 indications for assisted vaginal delivery
- suspected or anticipated fetal compromise
- delay in the 2nd stage of labour
- maternal effort contraindicated
What are the risks of a delayed 2nd stage of labour?
- increased chance of fetal compromise
- pelvic floor injury and sphincter dysfunction more likely
List the contraindications to instrumental delivery
- fetal bleeding disorders (e.g. alloimmune thrombocytopenia)
- predisposition to fracture e.g. osteogenesis imperfecta
- face presentation - vacuum contraindicated
- <34/40 CI for vacuum (between 34-36/40 unclear safety)
List the findings on abdominal and vaginal examination that would satisfy the requirements for instrumental vaginal birth
- Less than 1/5th palpable
- Cephalic
- cervix fully dilated, membranes ruptured
- exact position of head known
- caput and moulding and pelvis size considered
What are the steps required for preparation of mother for instrumental delivery?
- informed consent
- analgesia - regional ideally, pudendal acceptable in urgent delivery
- empty bladder - IDC removed or balloon deflated
- aseptic technique
List the preparation of staff required for an instrumental delivery
- knowledge and skill necessary from operator
- adequate facilities
- back up plan in case of failure to deliver (CS within 30 mins)
- senior obstetrician competent in performing mid cavity births should be present
- anticipation of shoulder dystocia, PPH
- personnel present that are trained in neonatal resuscitation
How is an outlet instrumental classified?
- fetal scalp visible without separating the labia
- fetal skull has reached the pelvic floor
- sagittal suture is in the OP diameter or right or left OA or posterior position (rotation does not exceed 45deg)
- fetal head is at or on the perineum
How would you classify a low instrumental delivery
- leading point of the skull (not caput) is at station +2 and not on the pelvic floor
- 2 subdivisions - rotation of 45 deg or less from the OA position, rotation of more than 45 deg including the OP position
How would you classify a mid cavity instrumental delivery?
fetal head is no more than 1/5th palpable per abdomen
leading point of the skull is above the station +2cm but not above the ischial spines
2 subdivisions - rotation of 45 deg or less from the OA position, rotation is more than 45 deg including the OP position
How would you classify a high cavity
- instrumental delivery not recommended in this setting
- 2/5th palpable abdominally
- Presenting part above the level of ischial spines
List 4 factors that are associated with failure of instrumental delivery?
- BMI >30
- EFW >4kg
- OP position
- Mid cavity or when 1/5 of fetal head palpable abdominally
What is the evidence behind performing an episiotomy for instrumental delivery?
In women having their first vaginal delivery an episiotomy
- results in 24% fewer OASIS when forceps used
- results in 16% fewer OASIS when ventouse used
Describe cup placement for vacuum extraction
- placement of cup at the flexion point
- flexion point = 6cm from anterior fontanelle, 3cm from posterior fontanelle
- in midline over the sagittal suture
enables flexion of the fetal head with traction improving chance of rotation of the head if necessary
