Operative delivery

Question 1

What is the goal of operative vaginal delivery?

Answer 1

The goal of operative vaginal delivery is to mimic spontaneous vaginal birth, thereby expediting delivery with a minimum of maternal or neonatal morbidity.

Question 2

Risk factors of operative vaginal delivery

Answer 2

a. Supine or lithotomy positions.
b. Epidural analgesia.
c. Primiparous women- primiparous women who received epidurals were likely to have fewer rotational or mid-cavity operative interventions when pushing was delayed for 1 to 2 hours or until they had a strong urge to push

Question 3

What causes higher rates of failure during operative vaginal delivery?

Answer 3

Maternal body mass index over 30.
EFW over 4000 g or clinically big baby.
OP position
Mid-cavity delivery or when 1/5th of the head palpable per abdomen.

Question 4

What are the classification of operative vaginal delivery?

Answer 4

Outlet
Low
Mid
High

Question 5

How does the baby present in the outlet position?

Answer 5

Fetal scalp visible without separating the labia.
Fetal skull has reached the pelvic floor.
Sagittal suture is in the anterio-posterior diameter or right or left occiput anterior or posterior position (rotation does not exceed 45º).
Fetal head is at or on the perineum

Question 6

How does the baby present in the low position?

Answer 6

Leading point of the skull (not caput) is at station plus 2 cm or more and not on the pelvic floor
Two subdivisions:
1. Rotation of 45º or less from the occipito-anterior position
2. Rotation of more than 45º including the occipito-posterior position

Question 7

How does the baby present in the mid position?

Answer 7

Fetal head is no more than 1/5th palpable per abdomen Leading point of the skull is above station plus 2 cm but not above the ischial spines

Two subdivisions:

1. rotation of 45º or less from the occipito-anterior position
2. rotation of more than 45º including the occipito-posterior position

Question 8

How does the baby present in the high position?

Answer 8

Not included in the classification as operative vaginal delivery is not recommended in this situation where the head is 2/5th or more palpable abdominally and the presenting part is above the level of the ischial spines

Question 9

What are the indications for instrumental vaginal delivery?

Answer 9

Presumed fetal compromise.

To shorten and reduce the effects of the second stage of labour on medical conditions (e.g. cardiac disease Class III or IV*, hypertensive crises, myasthenia gravis, spinal cord injury patients at risk of autonomic dysreflexia, proliferative retinopathy).

Inadequate progess

Maternal fatigue/exhaustion

Question 10

When should you consider instrumental delivery in nulliparous women with inadequate delivery?

Answer 10

Lack of continuing progress for 3 hours (total of active and passive second-stage labour)17 with regional anaesthesia, or 2 hours without regional anaesthesia.

Question 11

When should you consider instrumental delivery multiarous women with inadequate delivery?

Answer 11

Multiparous women – lack of continuing progress for 2 hours (total of active and passive second-stage labour)17 with regional anaesthesia, or 1 hour without regional anaesthesia

Question 12

What are the prerequistes for instrumental delivery?

Answer 12

Full abdominal and vaginal examination.
Preparation of mother.
Preparation of staff.

Question 13

What should you notice in a full abdominal and vaginal examination before commencing instrumental delivery?

Answer 13

Head is ≤1/5th palpable per abdomen
Vertex presentation.
Cervix is fully dilated, and the membranes ruptured.
Exact position of the head can be determined so proper placement of the instrument can be achieved.
Assessment of caput and moulding.
Pelvis is deemed adequate.
Irreducible moulding may indicate cephalo–pelvic disproportion.

Question 14

How should you prepare a mother for an instrumental delivery?

Answer 14

Clear explanation should be given and informed consent obtained.

Appropriate analgesia is in place for mid-cavity rotational deliveries. This will usually be a regional block. A pudendal block may be appropriate, particularly in the context of urgent delivery.

Maternal bladder has been emptied recently. In-dwelling catheter should be removed or balloon deflated. Aseptic technique.

Question 15

How should you prepare the staff for an instrumental delivery?

Answer 15

Operator must have the knowledge, experience and skill necessary.

Adequate facilities are available (appropriate equipment, bed, lighting).

Back-up plan in place in case of failure to deliver. When conducting mid-cavity deliveries, theatre staff should be immediately available to allow a caesarean section to be performed without delay (less than 30 minutes). A senior obstetrician competent in performing mid-cavity deliveries should be present if a junior trainee is performing the delivery.

Anticipation of complications that may arise (e.g. shoulder dystocia, postpartum haemorrhage).

Personnel present that are trained in neonatal resuscitation

Question 16

Which instruments should be used for instrumental delivery?

Answer 16

The operator should choose the instrument most appropriate to the clinical circumstances and their level of skill.
Forceps and vacuum extraction are associated with different benefits and risks. Failed delivery with selected instrument is more likely with vacuum extraction.

The options available for rotational delivery include Kielland forceps, manual rotation followed by direct traction forceps or rotational vacuum extraction.
d. Rotational deliveries should be performed by experienced operators, with the choice depending on the expertise of the individual operator.

Question 17

When should operative vaginal delivery be abandoned?

Answer 17

Operative vaginal delivery should be abandoned where there is no evidence of progressive descent with moderate traction during each contraction or where delivery is not imminent following three contractions of a correctly applied instrument by an experienced operator.

Question 18

What is involved in the care of the woman after instrumental delivery?

Answer 18

Women should be reassessed after an operative vaginal delivery for risk factors for venous thromboembolism and, if appropriate, thromboprophylaxis should be prescribed.

Regular paracetamol and diclofenac should be offered after an operative vaginal delivery in the absence of contraindications.

The timing and volume of the first void urine should be monitored and documented. A post-void residual should be measured if retention is suspected.

Question 19

When are women at risk of urine retention after instrumental delivery?

Answer 19

Women who have had a spinal anaesthetic or epidural that has been topped up may be at increased risk of retention.

Question 20

When should a vacuum extractor shouldn’t be used?

Answer 20

A vacuum extractor should not be used at gestations of less than 34 weeks +0 days.

The safety of vacuum extraction at between 34 weeks +0 days and 36 weeks +0 days of gestation is uncertain and should therefore be used with caution.

Question 21

What are the indications for a Caesarean section?

Answer 21

Cephalopelvic disproportion (use of pelvimetry is not advised).
Malpresentation - e.g., breech, transverse lie.
Multiple pregnancy.
Severe hypertensive disease in pregnancy
Fetal conditions: distress, iso-immunisation, very low birth weight.
Failed induction of labour.
Repeat caesarean section.
Pelvic cyst or fibroid
Maternal infection (eg, herpes, HIV)

Question 22

What are the classification for Caesarean section?

Answer 22

Category 1
Category 2
Category 3
Category 4

Question 23

What’s category 1?

Answer 23

Immediate threat to the life of the woman or foetus:
'Emergency section'.
Performed as quickly as possible.
Decision-to-delivery time will usually be within 30 minutes. This is not critical in influencing baby outcome but has been an accepted audit standard for response to emergencies within maternity services.
Possible indications:
1. Cord prolapse
2. Fetal distress in the first stage.
3. Antenatal haemorrhage

Question 24

What is category 2?

Answer 24

Maternal or fetal compromise which is not immediately life-threatening:
Decision-to-delivery time will usually be within 75 minutes.
Possible indications:
1) Failure to progress.
2) Transverse lie in labour.

Question 25

What is category 3?

Answer 25

No maternal or fetal compromise but needs early delivery:

i. Timing dependent on indication.

Question 26

What is category 4?

Answer 26

Delivery times to suit woman or staff:

i. Not routinely before 39 weeks.

Question 27

What is perimortem caesarean?

Answer 27

Should be performed following collapse if there is no cardiac output after four minutes.
Is performed primarily in the interests of maternal survival; confirming fetal well-being wastes time.
Is done on the spot - the mother is not moved to theatre.
No anaesthetic is necessary.
A scalpel is the only essential equipment.

Question 28

How do you do a Caesarean section?

Answer 28

• Ideally performed under spinal or epidural block. This has fewer risks and allows immediate contact between the baby and mother.
• There is evidence that prophylactic antibiotics result in fewer wound infections in non-elective and elective caesarean sections.
• Lower uterine segment incision is nearly always used now, as uterine rupture is much less common in subsequent pregnancies and it allows better healing, reduces infection and lowers postoperative complication rates:
• The transverse incision of choice should be the Joel Cohen incision (a straight skin incision, 3 cm above the symphysis pubis; subsequent tissue layers are opened bluntly and, if necessary, extended with scissors and not a knife), because it is associated with shorter operating times and reduced postoperative febrile morbidity.
• Oxytocin 5 IU by slow intravenous injection should be used to encourage uterine contraction and to decrease blood loss.
• The placenta should be removed using controlled cord traction, as this reduces the risk of endometritis.
• The uterine incision should be closed in two layers.
• Neither visceral nor parietal peritoneum should be sutured.

Question 29

What are the factors affecting Caesarean section rate?

Answer 29

• Place of birth: planned delivery at home or in a midwifery-led unit reduces the likelihood of caesarean section.
• Continuous support during labour reduces the likelihood of caesarean section.
• Induction of labour beyond 41 weeks in women with an uncomplicated pregnancy, because this reduces the risk of perinatal mortality and the likelihood of caesarean section.
• A partogram with a four-hour action line used to monitor progress of labour of women in spontaneous labour with an uncomplicated singleton pregnancy at term reduces the likelihood of caesarean section.
• Consultant obstetricians should be involved in the decision making for caesarean section, because this reduces the likelihood of caesarean section.

Question 30

What is external Cephalic Version?

Answer 30

External cephalic version (ECV) is the manipulation of the fetus, through the maternal abdomen, to a cephalic presentation.

Question 31

When should ECV be offered?

Answer 31

ECV should be offered from 36 weeks in nulliparous women and from 37 weeks in multiparous women.

Question 32

What are the contraindications of ECV?

Answer 32

Where caesarean delivery is required
Antepartum haemorrhage within the last 7 days
Abnormal cardiotocography
Major uterine anomaly Ruptured membranes
Multiple pregnancy (except delivery of second twin). Small-for-gestational-age fetus with abnormal Doppler parameters
Proteinuric pre-eclampsia
Oligohydramnios
Major fetal anomalies
Scarred uterus
Unstable lie.

Question 33

When should elective sections take place?

Answer 33

Planned caesarean section- should not take place before 39 weeks due to increased risk of respiratory morbidity.

Question 34

Who is offered elective sections?

Answer 34

Breech presentation- section offered if external cephalic version is CI.
Multiple pregnancy- planned section after 38 weeks
Preterm birth
Placenta praevia- Risk of placenta praevia is increased after previous caesarean section.

Question 35

What do elective sections reduce the risk of?

Answer 35

Perineal and abdominal pain during birth and three days postpartum.
Injury to vagina.
Early PPH
Obstetric shock

Question 36

What do elective sections increase the risk of?

Answer 36

Neonatal intensive care unit admission for the baby.

For the mother, a longer hospital stay, hysterectomy (necessitated to stem postpartum haemorrhage) and cardiac arrest.

Question 37

Complications of Caesarean section?

Answer 37

Lung aspiration
PE
PPH
Infection

Question 38

What are the normal movements of the fetal head in labour?

Answer 38

Engagement 
Descent and flexion 
Internal rotation 
Further descent 
Extension and delivery 
External rotation (restitution)

Question 39

What is engagement?

Answer 39

The fetal head enters the pelvic inlet in an occipitotransverse (OT) position because the transverse diameter of the inlet is greater than the anteroposterior diameter, and the fetal head is widest in its anteroposterior diameter.

Question 40

What is descent and flexion?

Answer 40

The head descend into the mid-cavity and flexes as the cervix dilates.

Question 41

What is internal rotation?

Answer 41

In the mid-cavity of the pelvis, the fetal head rotates through 90 degrees into an occipitoanterior (OA) position, remaining flexed.

It is when this process does not occur, or if the baby rotates to an occipitoposterior (OP) position, that prolonged or obstructed labour can occur, which might require rotation of the baby and either operative vaginal delivery or caesarean section.

Question 42

What is further descent?

Answer 42

The head continues its descent along the ischial spines, and the perineum distends.

Question 43

What is extension and delivery?

Answer 43

The head extend as it delivers.

Question 44

What is external rotation (restitution)?

Answer 44

Following the delivery of the head, the foetus rotates back to an OT position along with its shoulders.
Axial traction is then applied to allow delivery of the anterior shoulder, and then the posterior shoulder.

Question 45

What is shoulder dystocia?

Answer 45

Shoulder dystocia refers to a situation where, after delivery of the head, the anterior shoulder of the fetus becomes impacted on the maternal pubic symphysis, or (less commonly) the posterior shoulder becomes impacted on the sacral promontory.

Question 46

When does shoulder dystocia occur?

Answer 46

Shoulder dystocia occurs when there is impaction of the anterior fetal shoulder behind the maternal pubic symphysis, or impaction of the posterior shoulder on the sacral promontory.

A delay in delivery of the fetal shoulders leads to hypoxia in the fetus, proportional to the time delay to complete delivery.

Question 47

Risk factors for shoulder dystocia

Answer 47

Previous shoulder dystocia. 
Macrosomnia 
Diabetes 
Maternal BMI > 30 
Induction of labour 
Prolonged 1st stage of Labour 
Secondary arrest 
prolonged second stage of labour 
Augmentation of labour with oxytocin 
Assisted vaginal delivery

Question 48

Management of shoulder dystocia

Answer 48

REMEMBER – If managed appropriately the risk of permanent brachial plexus injury can be almost eliminated.

The immediate steps in the management of shoulder dystocia include:

Call for help – shoulder dystocia is an obstetric emergency (will need senior obstetrician, senior midwife and paediatrician in attendance).
Advise the mother to stop pushing – this can worsen the impaction.
Avoid downwards traction on the fetal head (increases risk of brachial plexus injury) – only use “routine” axial traction (i.e. keep the head in line with the baby’s spine), and do not apply fundal pressure (increases the risk of uterine rupture).
Consider episiotomy – this will not relieve obstruction but can make access for manoeuvres easier.

Question 49

First line manoeuvres for shoulder dystocia

Answer 49

McRoberts manoeuvre

Suprapubic pressure

Question 50

What is McRoberts manoeuvre?

Answer 50

hyperflex maternal hips (knees to chest position) and tell the patient to stop pushing. This widens the pelvic outlet by flattening the sacral promontory and increasing the lumbosacral angle. This single manoeuvre has a success rate of about 90% and is even higher when combined with ‘suprapubic pressure’.

Question 51

What is suprapubic pressure?

Answer 51

Suprapubic pressure is applied in either a sustained or rocking fashion to apply pressure behind the anterior shoulder to disimpact it from underneath the maternal symphysis.

Question 52

Second line manoeuvres for shoulder dystocia

Answer 52

Posterior arm – insert hand posteriorly into sacral hollow and grasp posterior arm to deliver.

Internal rotation (“corkscrew manoeuvre”) – apply pressure simultaneously in front of one shoulder and behind the other to move baby 180 degrees or into an oblique position.

If the above manoeuvres fail then roll patient onto all fours and repeat (this may widen the pelvic outlet as the legs are abducted and flexed).

Question 53

Complications of shoulder dystocia

Answer 53

The complications of shoulder dystocia can be divided into maternal and fetal:

Maternal – 3rd or 4th degree tears (3-4%), post-partum haemorrhage (11%).

Fetal – humerus or clavicle fracture, brachial plexus injury (2-16%), hypoxic brain injury.