10/11) Labour & Delivery - Operative vaginal delivery + consent advice

Question 1

Incidence of operative vaginal delivery

Answer 1

10-13%

Question 2

Things which reduce the need for operative delivery

Answer 2

• Continuous support in labour
• Upright or lateral position during second stage
• Avoiding epidural
• Passive hour (or longer if primip with epidural)

Question 3

Indications for operative delivery

Answer 3

• Fetal distress
• Shortened second stage (e.g. maternal cardiac 3/4 conditions, myasthenia gravis, proliferative retinopathy, hypertensive crises, spinal cord patients at risk of AD)
• Delay in second stage: Lack of continuous progress after 3 hours in primips with epidural (2 hours without) or 2 hours in multips with epidural (1 hour without).
• Maternal fatigue

Question 4

What is the consequence of delay >3 hours?

Answer 4

Increased maternal morbidity (no neonatal concerns provided adequate monitoring and prompt obstetric intervention)

Question 5

What is classed as an “outlet” operative vaginal delivery?

Answer 5

• Fetal scalp visible without parting labia
• <45 degrees of rotation from direct (either OA or OP)
• Fetal skull on pelvic floor
• Fetal head is on perineum

Question 6

What is classed as a “low” operative vaginal delivery?

Answer 6

• Fetal skull +2
• Rotational if >45 from OA
• Non-rotational if <45 from OA

Question 7

What is classed as a “mid” operative vaginal delivery?

Answer 7

• Fetal skull spines —> +2
• No more than 1/5 palpable abdominally
• Rotational or non-rotational

Question 8

Pre-requisites for operative vaginal delivery

Answer 8

• <1/5 palpable abdominally
• Fully dilated
• Membranes ruptured
• Vertex presentation
• Position known
• Station spines or below
• Pelvis thought to be adequate
• Assessment of caput and moulding made
• Explanation, consent, analgesia, bladder emptied, aseptic technique.
• Appropriate staff, facilities, back up plan, anticipation of complications and neonatal resus team.

Question 9

Factors associated with increased risk of failed instrumental delivery

Answer 9

BMI >30
EFW >4000g or clinically large baby
OP position
Mid cavity position or when 1/5 palpable abdominally

(Instrumentals with higher rate of failure should be conducted as trials)

Question 10

Comparison of ventouse and forceps

Answer 10

Compared to forceps, ventouse is:

• More likely to fail
• More likely to cause cephalohaematoma
• More likely to cause retinal haemorrhage
• More likely to be associated with maternal concerns re: baby
• Less likely to cause perineal trauma
• No difference in likelihood of CS, low 5 minute apgars or need for phototherapy.

Question 11

When to abandon instrumental delivery?

Answer 11

If no descent with moderate traction during each contraction or where delivery is not imminent following 3 contractions of correctly applied instrumental by experienced operator.

Question 12

When to send paired cord blood samples after instrumental?

Answer 12

Every time!

Question 13

Risk of intracranial haemorrhage with sequential instruments

Answer 13

1 in 256 deliveries with 2 instruments

1 in 334 deliveries for failed forceps —> CS

Question 14

Success rate for spontaneous vaginal delivery in future after instrumental

Answer 14

80%

Question 15

How long to leave catheter for after instrumental?

Answer 15

12 hours after spinal or epidural top up.

Question 16

Maternal risks with instrumental delivery (consent guidance)

Answer 16

• Episiotomy (5-6 in 10 ventouse, 9 in 10 forceps)
• Perineal grazes or superficial tears - Very common
• Significant vulval or vaginal tears - 1 in 10 ventouse, 1 in 5 forceps
• OASI - 1-4 in 100 ventouse, 8-12 in 100 forceps.
• PPH 1-4 in 10

Question 17

Fetal risks with instrumental delivery (consent guidance)

Answer 17

• Marks from forceps/ventouse - universal
• Scratches - 1 in 10
• Cephalhaematoma - 5/100 (1-12)
• Subgaleal haemorrhage - 5/1000 (3-6)
• Intraventricular haemorrhage - 5/10,000 (5-15)
• Facial nerve palsy very rare
• Retinal haemorrhage 17-38/100
• Jaundice 5-15/100