Instrumental Delivery

Question 1

What is instrumental delivery?

Answer 1

Instrumental delivery refers to a vagina delivery assisted by either a ventouse suction cup or forceps. Tools are used to help deliver the baby’s head. About 10% of births in the UK are assisted by an instrumental delivery.

Question 2

What should be done following instrumental delivery?

Answer 2

A single dose of co-amoxiclav is recommended after instrumental delivery to reduce the risk of maternal infection.

Question 3

Indications for instrumental delivery?

Answer 3

The decision to perform an instrumental delivery is based on the clinical judgement of the midwife or obstetrician. Some key indications are:

Failure to progress
Fetal distress
Maternal exhaustion
Control of the head in various fetal positions

TOM TIP: It is worth remembering there is an increased risk of requiring an instrumental delivery when an epidural is in place for analgesia.

Question 4

Risks of instrumental delivery?

Answer 4

Having an instrumental delivery increases the risk to the mother of:

Postpartum haemorrhage
Episiotomy
Perineal tears
Injury to the anal sphincter
Incontinence of the bladder or bowel
Nerve injury (obturator or femoral nerve)

The key risks to remember to the baby are:

Cephalohaematoma with ventouse
Facial nerve palsy with forceps

Rarely there can be serious risks to the baby:

Subgaleal haemorrhage (most dangerous)
Intracranial haemorrhage
Skull fracture
Spinal cord injury

Question 5

Main complication of forceps?

Rarer comps?

Answer 5

The main complication for the baby is facial nerve palsy, with facial paralysis on one side.

Forceps delivery can leave bruises on the baby’s face. Rarely the baby can develop fat necrosis, leading to hardened lumps of fat on their cheeks. Fat necrosis resolves spontaneously over time.

Question 6

Which nerves can be injured in the motor during instrumental delivery?

Answer 6

Rarely an instrumental delivery may result in nerve injury for the mother. This usually resolves over 6 – 8 weeks. The affected nerves may be:

Femoral nerve
Obturator nerve

The femoral nerve may be compressed against the inguinal canal during a forceps delivery. Injury to this nerve causes weakness of knee extension, loss of the patella reflex and numbness of the anterior thigh and medial lower leg.

The obturator nerve may be compressed by forceps during instrumental delivery or by the fetal head during normal delivery. Injury causes weakness of hip adduction and rotation, and numbness of the medial thigh.

Question 7

Nerve injuries which may occur in mother during normal delivery?

Answer 7

Three other nerve injuries can occur during birth that are usually unrelated to instrumental delivery:

Lateral cutaneous nerve of the thigh
Lumbosacral plexus
Common peroneal nerve

The lateral cutaneous nerve of the thigh runs under the inguinal ligament. Prolonged flexion at the hip while in the lithotomy position can result in injury, causing numbness of the anterolateral thigh.

The lumbosacral plexus may be compressed by the fetal head during the second stage of labour. Injury to this network of nerves nerve can cause foot drop and numbness of the anterolateral thigh, lower leg and foot.

The common peroneal nerve may be compressed on the head of the fibula whilst in the lithotomy position. Injury to this nerve causes foot drop and numbness in the lateral lower leg.