Special circumstances labour

Question 1

What does the successfulness of induction depend on?

Answer 1

state or ‘favourability’ of the cervix
scored out of 10, as the ‘Bishop’s score’
o ‘Consistency’
o Degree of effacement or early dilation
o How low the head is in the pelvis (station)
o Cervical position (anterior or posterior)

Question 2

What occurs with induction with prostaglandins?

Answer 2

gel or slow-release preparation is inserted into the posterior vaginal fornix
best method for nulliparous women and in multiparous women (unless the cervix is favourable)
it either starts labour or the ‘ripeness’ of the cervix is improved to allow amniotomy

Question 3

What occurs with induction with amniotomy +- oxytocin?

Answer 3

forewaters are ruptured with an amnihook
oxytocin infusion is then started within 2hrs if labour has not ensued
oxytocin is often used alone if spontaneous rupture of the membranes have already occurred, although PGs are as effective

Question 4

What occurs with natural induction?

Answer 4

cervical sweeping involves passing a finger through the cervix and ‘stripping’ between the membranes and the lower segment of the uterus
at 40 weeks, this reduces the chance of induction and postdates prengnancy, but can be uncomfortable

Question 5

What are the indications for induction?

Answer 5

• Foetal indications- high-risk situations
o Prolonged pregnancy
o Suspected IUGR or compromise
o Antepartum haemorrhage
o Poor obstetric history
o Prelabour term rupture of membranes (PROM)
• Materno-foetal indications- pre-eclampsia and maternal disease (eg. diabetes)
• Maternal indications- social reasons and in utero death
• Routine indications- studies show lowest perinatal and infant mortality rate is achieved by delivery at 38 weeks

Question 6

What are the contraindications for induction?

Answer 6

• Absolute contraindications
o Acute foetal compromise eg. abnormal CTG
o Abnormal lie
o Placenta praevia
o Pelvic obstruction
o >1 C-section
• Relative contraindications >1 C-section and prematurity

Question 7

What are the complications of induction?

Answer 7

• Induction commonly increases the time spent in ‘early labour’
• Labour may fail to start or be slow due to inefficient uterine activity or overactivity of the uterus hyperstimulation- foetal distress and even uterine rupture
CTG should be used for 1hr- oxytocin is commonly required in labour and also warrants CTG monitoring
PPH
Intrapartum/postpartum infection

Question 8

What are the contraindications for vaginal birth after C-section (VBAC)

Answer 8

o	All absolute indications for C-section
o	Vertical uterine scar
o	Previous uterine rupture
o	Multiple previous C-sections (≥2)
•	If a VBAC is attempted- 72-75% of women will deliver vaginally, the others will require an emergency C- section in labour

Question 9

Which factors are associated with increased success for VBAC?

Answer 9

o	Spontaneous labour
o	Interpregnancy interval <2yrs
o	Low age and BMI
o	Caucasian race
o	Previous vaginal delivery
o	Previous elective C-section or due to foetal distress (not dystocia)

Question 10

What are the risks of VBAC?

Answer 10

• Risk of maternal death is approx. 13 in 100,000- double planned C-section
• The overall risk of foetal mortality with VBAC is approx. the same risk as found in a 1st labour
• Delivery in hospital and with CTG monitoring is advised because of risk of scar rupture- induction is usually avoided as it is associated with a higher risk of rupture- augmentation also increased the risk of scar rupture

Question 11

How does scar rupture present?

Answer 11

o	Foetal distress
o	Scar pain
o	Cessation of contractions
o	Vaginal bleeding
o	Maternal collapse

Question 12

What is prelabour term rupture of the membranes?

Answer 12

• In 10% of women after 37 weeks- the membranes rupture before the onset of labour, 60% will start labour within 24hrs
gush of clear fluid, which is followed by an uncontrollable intermittent trickle
‘point of care tests’ (Actim PROM) may help where the diagnosis is not clear
• A few only have ‘hindwater’ rupture- liquor leaks, but membranes remain intact in front of the foetal head

Question 13

What are the risks of prelabour term rupture of the membranes (PROM)?

Answer 13

o Cord prolapse- rare and usually a complication of transverse lie or breech presentation
o Neonatal infection- small, but definite risk, increased by vaginal examination, presence of GBS and increased duration of rupture

Question 14

What are the management options for PROM?

Answer 14

o Spontaneous labour- wait for <24hrs, presence of meconium or evidence of infection warrants immediate induction, after 18-24hrs, prophylactic antibiotics given against GBS and to induce labour
o Induced labour- does not increase risk of C-section and associated with lower chance of maternal infection

Question 15

What is the aim of an instrumental delivery?

Answer 15

• Allows the use of traction if delivery needs to be expedited in the 2nd stage
rotation may be required and in the absence of rotation, then instrumental delivery simply add power
• The aim is to prevent foetal and maternal morbidity associated with a prolonged 2nd stage or expedite where the foetus is compromised
• In the UK, approx. 20% of nulliparous and 2% of multiparous women are delivered by forceps or ventouse

Question 16

What are ventouse?

Answer 16

• Consists of a 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 positioned head
often allows the shape of the pelvis to simultaneously rotate a malpositioned head to the OA position

Question 17

What are obstetric forceps?

Answer 17

• 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 18

What are non-rotational forceps?

Answer 18

e.g Simpson’s- grip the head in whatever position it is in and allows traction
only suitable for OA position- have a cephalic curve for the head and a pelvic curve which follows the sacral curve

Question 19

What are rotational forceps?

Answer 19

e.g keilland’s- have no pelvic curve and enable a malpositioned head to be rotated by the operator to an OA position before traction is applied

Question 20

What are the complications of using forceps and ventouse?

Answer 20

• Maternal complications- need for analgesia is greater with forceps, use of either instrument can cause vaginal lacerations, 3rd degree tears and PPH
• Foetal complications- slightly worse with ventouse, ‘chignon’ (swelling on scalp) is usual as it is drawn in with suction of the cup, scalp lacerations, cephalhaematoma and neonatal jaundice are 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 21

What happens when the instrument is changed?

Answer 21

this is associated with increased foetal trauma
usually only appropriate (only once) if the ventouse has achieved decents to the pelvic outlet, but then comes off the head and is replaced by a low cavity forceps delivery

Question 22

What are the indications for an instrumental vaginal delivery?

Answer 22

• Prolonged 2nd stage- usual if 1-2hrs of pushing has failed to deliver the baby
Foetal distress
• Prophylactic use- indicated to prevent pushing in women with medical problems (e. severe cardiac disease or hypertension)
• Breech delivery- forceps are occasionally applied to the after-coming head

Question 23

What is a low cavity delivery?

Answer 23

• Head is well below the ischial spines- bony prominences palpable vaginally on the lateral wall of the mid- pelvis- usually OA position
• Forceps or ventouse are appropriate- latter better if maternal effort is poor, pudendal block with perineal infiltration is usually sufficient analgesia

Question 24

What is a mid-cavity delivery?

Answer 24

• Head is engaged, but at or just below the level of the ischial spines- epidural or spinal anaesthesia is usual
OT position- ventouse- rotation in situ followed by descent can also be achieved by manual
rotation or Kielland’s rotational forceps
OP position- dragging out a baby in this position may fail or cause severe perineal damage, rotation of 180O can be achieved manually or with the ventouse/Kielland’s forceps

Question 25

What are the prerequisites for instrumental vaginal delivery?

Answer 25

• The 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
• The position of the head must be known
• There must be adequate analgesia
• The bladder should be empty