Induction of labour



Induction of labour may be considered when there is a medical indication, or when the benefits outweigh the risks.

I gave a talk in Auckland at the Royal Australian New Zealand College of Obstetricians and Gynaecologists Annual Scientific Meeting 2017 entitled "Induction of Labour - New Indications".  Please click here if you want to listen to this talk. It is about 30 minutes and meant for obstetricians and gynaecologists, but has been structured so that patients may still be able to understand this. I would be happy to discuss this further with you if required.


More recently, data has been accumulated to strongly suggest that induction of labour is associated with lower risks for the mother and the baby than expectant management till 41 weeks and then induction of labour.

The ARRIVE trial has also shown that induction of labour for low risk nulliparous women at 39 weeks is associated with a lower Caesarean section rate and lower rate of neonatal respiratory morbidity.

Problems of induction of labour include risks of:

- failed induction of labour (higher if cervix is unfavourable and nulliparous)

- longer duration spent in the labour ward

- increased need for analgesia e.g. epidural during labour

Older studies showed an increased chance of Caesarean section when comparing induction of labour versus spontaneous labour. Newer studies that compare induction of labour compared with expectant management <or waiting> (which may result in spontaneous labour or induction of labour later in gestation) does not increase (and may even reduce the risk) of Caesarean section. It is more appropriate to compare induction of labour with expectant management (as those are the 2 options available e.g. when you are at 39 weeks), rather than to compare induction of labour with spontaneous labour (as spontaneous labour is not an option available). When compared this way, it has been shown that induction of labour does not increase Caesarean section but may instead reduce Caesarean section rate.

If you had a previous Caesarean section, I would generally avoid induction of labour with drugs because of a higher risk of uterine rupture with induction of labour.

Potential benefits of induction of labour may include:

- lower risk of big babies and risk of shoulder dystocia, Caesarean section, third degree tears

- lower risk of unexplained stillbirth, meconium-stained liquor, meconium aspiration syndrome

Method of induction proposed includes:

1. cervical sweep (which may cause discomfort and have bleeding)

2. 1-2 prostaglandin pessaries to soften the cervix (which may be associated with nausea, diarrhea, fever, hyperstimulation) and

3. intravenous oxytocin to stimulate uterine contractions (which may be associated with nausea, vomiting, hyperstimulation).

How to reduce the rates of Caesarean section with induction of labour at 39-40 weeks?

In general, the Caesarean section rate for a patient who undergoes induction of labour at 39-40 weeks are as follows:

1. women who had delivered babies vaginally before (without a uterine scar) - 4%

2. women in their first pregnancy - 22%

Caesarean section rates from induction of labour can be reduced by allowing at least 15 hours of intravenous oxytocin use to determine if labour has progressed beyond 5-6 cm.


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