Instrumental and Operative Delivery

Question 1

How do forceps or ventouse aid delivery?

Answer 1

Allow use of traction if delivery needs to be expedited in the 2nd stage

rotation, and power

Aim = prevent foetal and maternal morbidity associated with prolonged 2nd stage or expedite where the foetus is compromised

Question 2

What is a ventouse?

Answer 2

plastic, rubber or metal cap connected to a handle - the cap is fixed near the foetal occiput by suction

Traction during maternal pushing will deliver the OS position head - it often also allows the shape of the pelvis to simultaneously rotate a malpositioned head to the OA position

Question 3

How do obstetric forceps work?

Answer 3

come in pairs that fit together for use - each has a ‘blade’, shank, lock and handle.

When assembled, the blade fits around the foetal head and the handles fit together

the lock prevents them from slipping apart

Question 4

How do non-rotational forceps work?

Answer 4

grip the head in whatever position it is in and allows traction - only suitable for OA position.

They have a cephalic curve for the head and a pelvic curve which follows the sacral curve

Question 5

What do rotational forceps do?

Answer 5

Have no pelvic curve and enable a malpositioned head to be rotated by the operator and an OA position before traction is applied

Question 6

What are the complications of ventouse and forceps?

Answer 6

The key risks to remember to the baby are:

Cephalohaematoma with ventouse
Facial nerve palsy with forceps / bruising with forceps

Question 7

What method is more likely to fail - ventouse or forceps?

Answer 7

Ventouse - he cup can be placed inaccurately

Question 8

What are the maternal complications of instrumental delivery?

Answer 8

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

Question 9

What are the foetal complications of instrumental delivery?

Answer 9

Slightly worse with ventouse - chignon (swelling on scalp) - drawn with suction of cup

scalp lacerations, Cephalhaematomae and neonatal jaundice all more common with ventouse

facial bruising, facial nerve damage and skull fractures can occasionally occur with injudicious use of forceps and prolonged traction by either instrument is dangerous

Question 10

What are the indications for instrumental vaginal delivery?

Answer 10

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

Question 11

What is a low-cavity delivery?

Answer 11

Head is well below the ischial spines - bony prominences palpable vaginally on the lateral wall of the mid-pelvis - usually OA position

Question 12

How can instruments be used to aid low-cavity delivery?

Answer 12

Both appropriate - ventouse better if maternal effort is poor - pudendal block with perineal infiltration is usually sufficient analgesia

Question 13

What is mid-cavity delivery?

Answer 13

Head is engaged, but at or just below the level of the ischial spines - epidural or spinal anaesthesia is usual

If there is any doubt that delivery will be successful, it is attempted in the operating theatre, with full preparations for a C-section

Question 14

In what abnormal positions can instruments be used?

Answer 14

OA - forceps or ventouse

OT - usually the result of insufficient descent of the head to make it rotate - descent is achieved with ventouse - rotation in situ followed by descent can also be achieved by manual rotation or Kiellan’s rotational forceps

OP - often accompanied by extension of the foetal head, making the presenting diameter too large for the pelvis - dragging out a baby in this position may fail or cause severe perineal damage. rotation of 180 degrees can be achieved manually or with the ventouse/Kielland’s forceps

Question 15

What are the prerequisites for instrumental vaginal delivery?

Answer 15

Head must not be palpable abdominally

On vaginal examination, the head must be at or below the level of the ischial spines

The cervix must be fully dilated

position of the head must be known

There must be adequate analgesia

The bladder should be empty

Question 16

What % of births in the developed world are by C-section?

Answer 16

25%

Question 17

What is the usual operation for C-section?

Answer 17

LSCS

abdominal wall is opened with a suprapubic transverse incision - the lower segment of the uterus is also incised transversely to deliver the baby

Question 18

When is an emergency C-section performed?

Answer 18

labour - may also occur with acute antepartum problems e.g. placental abruption

Prolonged first stage

Foetal distress

Question 19

What is the diagnosis of a prolonged 1st stage?

Answer 19

when full dilation is not imminent by 12-16 hours or earlier if labour was initially rapid

Occasionally, full dilation achieved, but not all the criteria for instrumental delivery are met. Most commonly, it is due to abnormalities of the ‘powers’ - e.g. insufficient uterine action - the passenger or passage may also contribute

Question 20

What is an elective C-section? When is it needed?

Answer 20

Performed to avoid labour - normally at 39 weeks as this reduces the risk of transient tachypnoea of the newborn from 6% (38 weeks) to 4%. If earlier, administration of steroids should be considered

When delivery is needed before 34 weeks, usual to perform C-section rather than induce labour (pre-eclampsia and severe IUGR)

Question 21

What are the absolute indications to elective C-section?

Answer 21

placenta praevia
severe antenatal foetal compromise
uncorrectable abnormal lie 
previous vertical c-section 
gross pelvic deformity

Question 22

What are the relative indications of elective C-section?

Answer 22

breech presentation
severe IUGR
twin pregnancy
certain medical disorders
Previous C-section
Older nulliparous patients

Question 23

What are the maternal complications of C-section?

Answer 23

haemorrhage
need for blood transfusion
infection of the uterus or wound
damage to surrounding structures e.g. bladder or bowel damage

post-operative pain and immobility

VTE

Question 24

What prophylaxis Is given for C-sections?

Answer 24

H2 receptor antagonists (e.g. ranitidine) or proton pump inhibitors (e.g. omeprazole) before the procedure
Prophylactic antibiotics during the procedure to reduce the risk of infection
Oxytocin during the procedure to reduce the risk of postpartum haemorrhage
Venous thromboembolism (VTE) prophylaxis with low molecular weight heparin

Question 25

What are the foetal complications of C-section?

Answer 25

elective procedure increases the risk of foetal respiratory morbidity at any given gestation - in uncomplicated pregnancy, it is not recommended before 39 weeks

Fetal lacerations

Bonding and breastfeeding - affected by emergency procedures

Question 26

What is the effect of c-section on subsequent pregnancies?

Answer 26

Increased risk of repeat caesarean
Increased risk of uterine rupture
Increased risk of placenta praevia
Increased risk of stillbirth