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 8 or more predicts successful induction of labor, <8 suggests cervical ripening may be required to prepare the cervix

Question 4

What are the options for induction of labour?

Answer 4

• membrane sweep
• vaginal prostaglandin E2(dinoprostone)
• cervical ripening balloon (CRB)
• artificial rupture of membranes with oxytocin infusion
• Oral mifepristone and misoprostol are used to induce labour where intrauterine fetal death has occurred

Question 5

How does a membrane sweep help induce labour?

Answer 5

• 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 6

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

Answer 6

• 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 7

How does a cervical ripening balloon CRB help induce labour?

Answer 7

• 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 8

How is induction of labour monitored?

Answer 8

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

Question 9

What is the ongoing management options for IOL?

Answer 9

-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 10

What is the main complication of IOL with vaginal prostaglandins?

Answer 10

Uterine hyperstimulation

Question 11

What is uterine hyperstimulation?

Answer 11

-where contraction of uterus is prolonged and frequent causing fetal distress and compromise
-the two criteria for UH are:
>Individual uterine contractions lasting more than 2 minutes in duration
>More than five uterine contractions every 10 minutes

Question 12

What can uterine hyperstimulation lead to?

Answer 12

• Fetal compromise, with hypoxia and acidosis
• Emergency caesarean section
• Uterine rupture

Question 13

What is the management of uterine hyperstimulation?

Answer 13

• Removing the vaginal prostaglandins, or stopping the oxytocin infusion
• Tocolysis with terbutaline