Induction of labour

Question 1

When is IOL usually offered?

Answer 1

-between 41 and 42 weeks 
also offered in:
-prelabour ROM
-FGR
-pre-eclampsia
-obstetric cholestasis
-existing diabetes
-intrauterine fetal death

Question 2

What score is used to determine whether to induce labour?

Answer 2

Bishop score

Question 3

What are the five things assessed and scored in the Bishop score?

Answer 3

• Fetal station (0-3)
• Cervical position (0-2)
• Cervical dilation (0-3)
• Cervical effacement (scored 0-3)
• Cervical consistency (scored (0-2)

Total store out of 13

a score of < 5 indicates that labour is unlikely to start without induction

a score of ≥ 8 indicates that the cervix is ripe, or ‘favourable’ - there is a high chance of spontaneous labour, or response to interventions made to induce labour

<8 suggests cervical ripening may be required to prepare the cervix

Question 4

What are the options for induction of labour?

Answer 4

1. membrane sweep
2. vaginal prostaglandin E2(dinoprostone): pessary (PROPESS, inserted if membrane sweep not successful >24 hours )
3. vaginal prostaglandin E2 gel or tablet (PROSTIN, can be repeated after 6 hours)
   4.Cervical ripening balloon (CRB)
4. artificial rupture of membranes (amnihook)
5. ARM with oxytocin infusion (syntocinon)

• artificial rupture of membranes with oxytocin infusion
• Oral mifepristone and misoprostol are used to induce labour where intrauterine fetal death has occurred

Question 5

what is used for IOL if foetal death has occured?

Answer 5

Oral mifepristone (anti-progesterone) plus misoprostol are used to induce labour where intrauterine fetal death has occurred.

Question 6

How does a membrane sweep help induce labour?

Answer 6

• involves inserting a finger into cervix to stimulate the cervix and begin process of labour
• can be performed in antenatal clinic and if successful should produce onset of labour within 48 hours
• is not considered a full method of IOL but more of an assistance before full IOL
• used from 40 weeks

Question 7

How does a vaginal prostaglandin E2 (dinoprostone) help induce labour?

Answer 7

• involves inserting gel, tablet(prostin) or pessary (propess) into the vagina (pessary is similar to a tampom that slowly releases prostaglandins over 24hrs)
• stimulates cervix and uterus and causes onset of labour
• usually done in hospital setting so woman can be monitored before being allowed home to await full onset of labour

Question 8

How does a cervical ripening balloon CRB help induce labour?

Answer 8

• a silicone balloon is inserted into cervix and gently inflated to dilate it
• used as alternative to vaginal prostaglandins, usually in women with previous c-section, where prostaglandins have faiuled or multiparous women (>3)

Question 9

How is induction of labour monitored?

Answer 9

• CTG -> to assess fetal hR and uterine contractions before and during IOL
• Bishop score before and during IOL to monitor progress

Question 10

What is the ongoing management options for IOL?

Answer 10

-most women will give birth within 24 hours of start of IOL
-the options when there is slow or no progress are
>further vaginal prostaglandins
>artificial ROM and oxytocin infusion
>CRB
>elective c-section

Question 11

What is the main complication of IOL with vaginal prostaglandins?

Answer 11

Uterine hyperstimulation (tachysystole)

Question 12

What is uterine hyperstimulation?

Answer 12

-where contraction of uterus is prolonged and frequent causing fetal distress and compromise
-the two criteria for UH are:

1. Individual uterine contractions lasting more than 2 minutes in duration
2. More than 5 uterine contractions every 10 minutes

Question 13

What can uterine hyperstimulation lead to?

Answer 13

1. Fetal compromise, with hypoxia and acidosis
2. Emergency caesarean section
3. Uterine rupture

Question 14

What is the management of uterine hyperstimulation?

Answer 14

1. Removing the vaginal prostaglandins, or stopping the oxytocin infusion
2. Tocolysis with terbutaline

Question 15

Bishop score mnemonic:

Answer 15

Call PEDS For Parturition =Cervical consistency, Position, Effacement, Dilation, Fetal Station.

or

“: Pregnancy Can Enlarge Dainty Stomachs!

(Position, Consistency, Effacement, Dilation, Station).”

Question 16

what should be done if if the Bishop score is ≤ 6?

Answer 16

-vaginal prostaglandins or oral misoprostol

-mechanical methods such as a balloon catheter can be considered if the woman is at higher risk of hyperstimulation or has had a previous caesarean

Question 17

what should be done if the Bishop score is > 6?

Answer 17

amniotomy and an intravenous oxytocin infusion

Question 18

Order of Induction of labour:

Answer 18

1. Membrane sweep - inserting a gloved finger into the external os and separating the membranes from the cervix
2. Vaginal prostaglandins (PGE2)
3. Amniotomy - artificial rupture of membranes
4. Balloon catheter

Question 19

prolonged labour & causes:

Answer 19

Membrane sweep - inserting a gloved finger into the external os and separating the membranes from the cervix
Vaginal prostaglandins (PGE2)
Amniotomy - artificial rupture of membranes
Balloon catheter

Question 20

A 24-year-old woman is attending for labour induction for a large-for-dates baby at 38+2 weeks gestation.

Her observations are as follows:

Heart rate: 66 beats per minute
Blood pressure: 124/76 mmHg
Respiratory rate: 18 breaths per minute
Oxygen saturations: 100% on room air
Temperature: 36.7°C
A cardiotocograph is performed, which is reassuring.

A midwife performs a vaginal examination and describes her cervix as long, closed, firm, and posterior. Her Bishops score is 0.

What is the most appropriate management?

A. Intravaginal prostaglandin E2 analogue e.g. Propess

B. Artificial rupture of membranes

C. Intravenous oxytocin

D. Foley intracervical balloon catheter

E. An oral prostaglandin E1 analogue, e.g. misoprostol every 4 hours

Answer 20

A. Intravaginal prostaglandin E2 analogue e.g. Propess

Intravaginal prostaglandin E2 analogues such as Propess and Prostin are the first-line treatment in the induction of labour where there are no contraindications. These aim to soften and ripen the cervix in preparation for labour.

Not: B: ARM/amniotomy

An artificial rupture of membranes (ARM) can only be performed where the cervix is favourable, the foetus is well engaged, and there is space to access the cervical os.

Not D: Foley catheter

This woman’s cervix is described as very unfavourable, therefore insertion of a balloon catheter may be impossible. She has no contraindications to induction of labour using intravaginal prostaglandin E2 analogues such as Propress and Prostin.

Not E: An oral prostaglandin E1 analogue, e.g. misoprostol every 4 hours

Misoprostol is only used in the UK to induce labour in cases of foetal demise.

Question 21

Indications for induction of labour:

Answer 21

1. Post-dates i.e. >41 weeks gestation
2. Preterm prelabour rupture of membranes
3. Intrauterine foetal death
4. Abnormal CTG
5. Maternal conditions such as pre-eclampsia, diabetes, cholestasis

Question 22

Contraindications to IOL:

Answer 22

1. Previous classical/vertical incision during caesarean section
2. Multiple lower uterine segment caesarean sections
3. Transmissible infections e.g. herpes simplex
4. Placenta praevia
5. Malpresentations
6. Severe foetal compromise
7. Cord prolapse
8. Vasa previa

Question 23

what type of prostaglandin is given for IOL? (what PG receptors does it act on)?

Answer 23

Dinoprostone
-PgE2 analogue

Question 24

NICE guidelines (Bishop score <6 or >6)

Answer 24

if the Bishop score is ≤ 6
vaginal prostaglandins E2 (dinoprostone) (gel, tablet aka Prostin or pessary aka Propess) or oral misoprostol (prostaglandin E1 analogue)

-mechanical methods such as a balloon catheter can be considered if the woman is at higher risk of hyperstimulation or has had a previous caesarean

if the Bishop score is > 6
amniotomy and an intravenous oxytocin infusion