Induction of labour is now so common that in many NHS trusts it accounts for over a third of all births. The rise in induction rates reflects both the evidence supporting earlier intervention in certain circumstances (the ARRIVE trial and NICE NG207 guidance have influenced practice in post-dates pregnancy) and cultural and clinical shifts in risk tolerance.
Women offered induction sometimes feel it is being pushed on them without adequate information. The decision to be induced or to wait (expectant management) involves a genuine trade-off between the risk of continuing the pregnancy and the risks and inconveniences of the induction process itself — and different women in the same clinical situation may reasonably reach different decisions.
Healthbooq (healthbooq.com) covers pregnancy, birth, and maternity care.
Why Induction Is Offered
The most common indication is post-dates pregnancy — pregnancy continuing beyond 41 to 42 weeks. The placenta begins to function less efficiently after 40 to 41 weeks, and the risk of stillbirth increases with gestation. NICE NG207 (2021) recommends offering induction of labour at 41 weeks (seven days past the due date), with induction by 42 weeks if not already in labour.
The ARRIVE trial (Grobman et al., NEJM 2018) found that elective induction at 39 weeks in low-risk nulliparous (first-time) women did not increase caesarean rates compared to expectant management and slightly reduced some adverse outcomes, influencing an expansion of induction discussions in some settings.
Other common indications: ruptured membranes before labour (PROM or PPROM), gestational diabetes (typically induced at 38 to 39 weeks), pre-eclampsia, intrauterine growth restriction, decreased foetal movements with clinical concern, Group B Streptococcus carrier status in certain protocols, and maternal request (elective induction at term, discussed case by case).
Methods of Induction
Membrane sweep: the midwife or obstetrician inserts a finger through the cervix (if it is sufficiently dilated) and sweeps the membranes from the lower segment of the uterus, releasing prostaglandins. It is performed in the community or as an outpatient procedure, usually from 38 to 40 weeks. It increases the likelihood of spontaneous labour within 48 hours but does not always work; it can cause cramping, spotting, and discomfort. It does not affect the baby.
Prostaglandin pessary or gel: a prostaglandin preparation (dinoprostone or misoprostol) is inserted into the vagina. This ripens the cervix (softens, effaces, begins to dilate it) and may stimulate contractions. Multiple doses are sometimes required. A slow-release pessary (Propess) can be inserted and remain in place for up to 24 hours. Prostaglandin induction begins in hospital with foetal monitoring.
Foley catheter balloon: a catheter with an inflatable balloon is inserted through the cervix into the lower uterine segment; the balloon is inflated and mechanically dilates the cervix. Can be used when prostaglandins are contraindicated (e.g., previous caesarean). Evidence suggests broadly similar efficacy to prostaglandins.
Artificial rupture of membranes (ARM) plus IV oxytocin: once the cervix is sufficiently dilated, the membranes are ruptured with a small hook, and a synthetic oxytocin (syntocinon) infusion is started via a drip to stimulate contractions. This is the active phase of induction; continuous electronic foetal monitoring is required. IV oxytocin often produces stronger contractions than spontaneous labour, which is one reason for the higher epidural use in induced labours.
What Induction Means for Labour
Induction generally takes longer than awaited spontaneous labour. The cervical ripening phase can take several hours to over 24 hours. Many women find induced labour more intense than expected.
Epidural rates are higher in induced labours, primarily because the contractions from IV oxytocin can be more frequent and intense than spontaneous contractions, and because the process is longer.
Caesarean rates: induction versus expectant management at term has a similar overall caesarean section rate — this was one of the main findings of both ARRIVE and systematic reviews. This counters the common belief that induction inevitably leads to caesarean.
Continuous electronic foetal monitoring (CTG) is required during oxytocin induction, which limits mobility. Some women find this the most difficult aspect of an induced labour.
Decision-Making
Women should be given information about their specific indication, the benefits and risks of induction, the alternative of expectant management and its associated risks, and the methods available. Shared decision-making and informed consent are central to NICE guidance on induction. Women can decline induction; if they do, increased monitoring (daily CTG, growth scans) is typically offered.
Key Takeaways
Induction of labour is the process of artificially starting labour before it begins spontaneously. Approximately 35 per cent of labours in England are induced. Common indications include post-dates pregnancy (typically offered at 41 to 42 weeks), ruptured membranes without onset of labour, gestational diabetes, pre-eclampsia, intrauterine growth restriction, and certain maternal medical conditions. Methods include membrane sweep, prostaglandin vaginal pessary or gel, Foley catheter balloon, and IV oxytocin with artificial rupture of membranes. Induction takes longer than awaited spontaneous labour in most cases and carries a slightly higher rate of epidural use and instrumental delivery, though the overall caesarean rate is similar to expectant management at term.
