INDUCTION OF LABOUR

Induction of labour is the planned treatment that stimulates childbirth and delivery prior to its spontaneous onset. Inducing labour can be accomplished with pharmaceutical or non-pharmaceutical methods. Every year, 1 in 5 labours are induced in the UK.
Most women go into labour naturally (spontaneously) by the time they’re 42 weeks pregnant.
Induction is offered to all women who don’t go into labour naturally by 42 weeks, as there’s a higher risk of stillbirth or problems for the baby if pregnancy exceeds 42 weeks.
Other indications for induction include circumstances when there is increased risk to mother or baby, for example high blood pressure, pre-eclampsia or the baby isn’t growing. Once active labour is established, maternal and foetal monitoring should be carried out
Spontaneous rupture of membranes more than 24 hours before labour starts, has an increased risk of infection and is an indication for induction.
There are a number of absolute contraindications to induction including placenta praevia and severe foetal compromise.
It is therefore usually a medical decision to deal with a specific problem. There is however an argument in favour of inducing all women at term or shortly after.
Induction of labour for improving birth outcomes for women at or beyond term Philippa Middleton, Emily Shepherd, Caroline A Crowther
First published: 9 May 2018 Editorial Group: Cochrane Pregnancy and Childbirth Group
Summary
To assess the effects of a policy of labour induction at or beyond term compared with a policy of awaiting spontaneous labour, or until an indication for birth induction of labour is identified, on pregnancy outcomes for infant and mother.
A policy of labour induction at or beyond term compared with expectant management is associated with fewer perinatal deaths and fewer caesarean sections; but more operative vaginal births. NICU admissions were lower and fewer babies had low Apgar scores with induction. No important differences were seen for most of the other maternal and infant outcomes.

Methods of Induction
Methods of inducing labour include both pharmacological medication and mechanical or physical approaches.
Pharmaceutical
• Prostaglandin E2 is the most studied compound and with most evidence behind it. A range of different dosage forms are available with a variety of routes possible. Vaginal PGE2 should not be used if there are specific clinical reasons for not using it (in particular the risk of uterine hyper-stimulation).
• Intravenous administration of synthetic oxytocin preparations.
Non-pharmaceutical
• “Membrane sweep”, also known as membrane stripping, or “stretch and sweep” during an internal examination, the practitioner moves their finger within the cervix to stimulate and/or separate the membranes around the baby from the cervix. This causes a release of prostaglandins which can help to kick-start labour.
• Artificial rupture of the membranes (AROM or ARM) (“breaking the waters”) which is usually done immediately following a membrane sweep.
• Cervical balloons catheters and laminaria tents are not used routinely for induction of labour.

The most recent reviews on the subject of induction and its effect on Caesarean section indicate that there is no increase with induction and in fact there can be a reduction.
Ekaterina Mishanina et al., “Use of labour induction and risk of caesarean delivery: a systematic review and meta-analysis”, April 2014, Canadian Medical Association Journal
Summary
Our meta-analysis showed that the risk of caesarean delivery following labour induction was significantly lower than the risk associated with expectant management. This finding supports evidence from systematic reviews but is contrary to prevalent beliefs and information from consumer organizations, guidelines and textbooks. Labour induction was associated with benefits for the fetus and no increased risk of maternal death.

How effective is amniotomy as a means of induction of labour? 2010, 179 (3):381-3 Ir J Med Sci
Summary
In total, 26,670 women delivered in the National Maternity Hospital during the study period. Of these 4,928 women required induction of labour and 72.8% of these (n = 3,586) underwent amniotomy only for induction of labour. Spontaneous labour occurred in 90.1% of the women who underwent amniotomy within 24 h. Oxytocin as an induction agent was employed in 9.8% of cases. Overall, 80.5% of the women had a spontaneous delivery, 7.3% had a ventouse delivery, 4.3% had a forceps delivery, and 7.9% underwent a caesarean section. CONCLUSIONS: Amniotomy is a simple, safe and effective method of induction of labour.

If there is a medical indication to induce labour then the decision had been taken to deliver that patient within 24 hours. Induction is an active process and should not be dependent on suitability unless the alternative is immediate caesarean section.

References
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