Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Induction of labour and cervical ripening
Obstetrics and gynaecology · UK scope · Sources checked 7 Sept 2026 · Clinical review pending
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Excessive uterine activity or fetal compromise
Frequent or prolonged contractions during induction can reduce the interval for placental reperfusion and cause fetal compromise. Persistent pain, bleeding or maternal instability also requires assessment for rarer complications such as uterine rupture.
Action: Seek urgent midwifery and obstetric review, assess the fetal heart with cardiotocography and stop further induction medication or oxytocin. Remove a vaginal delivery system when possible, reposition away from supine and consider acute tocolysis. If fetal or maternal compromise persists, prepare to expedite birth.
Purpose and principles
Select an induction method from the indication, cervical assessment and uterine history, and recognise complications that require treatment to stop or the birth plan to change.
Induction is a sequence of decisions, not a single drug administration. The reason for recommending birth establishes how much time is available, while cervical readiness helps determine how labour can be initiated. A patient with an unfavourable cervix may need a ripening stage before amniotomy becomes feasible. Contractions can begin during ripening, but cervical change, fetal wellbeing and the response to each intervention remain important before moving to the next step.
Common reasons include prolonged pregnancy, prelabour membrane rupture and maternal or fetal conditions in which continuing pregnancy may be less favourable than birth. The indication should be expressed in patient-specific terms. NICE recommends discussing induction from 41+0 weeks because some risks rise as pregnancy continues; this does not make induction compulsory. If induction is declined, explain the limitations of surveillance and agree a continuing care plan. The person's preferences and consent can change during a process that may take more than a day.
Key points
Induction starts labour artificially; cervical ripening prepares an unfavourable cervix and may be only the first step.
Indications, selection and cautions
Indication and urgency
Confirm gestational age, the clinical reason for induction and whether vaginal birth is appropriate. An urgent maternal or fetal indication may leave insufficient time for routine ripening. Placenta praevia, unsuitable fetal lie or other contraindications to vaginal birth require a different route of birth rather than an induction method.
The Bishop assessment
The Bishop score incorporates cervical dilatation, effacement or length, consistency, position and the station of the presenting part. It estimates readiness rather than guaranteeing success. Record the findings as well as the total so that subsequent examinations can show how the cervix has changed.
Uterine scar and treatment history
Review previous caesarean or other uterine surgery, prior births, current contractions and any induction drugs already administered. Dinoprostone and misoprostol product restrictions are particularly important with a uterine scar. Do not select a regimen based only on the numerical Bishop score.
Patient experience and practical needs
Discuss vaginal examinations, discomfort, analgesia, monitoring, the possibility of several steps and potential delay between ripening and labour ward transfer. Assess language, support and transport needs. An agreed plan should also explain what happens if the patient wishes to pause or stop induction.
Red flags requiring action
Five or more contractions in ten minutes sustained for at least twenty minutes, or a prolonged contraction, requires prompt assessment rather than another induction dose.
Assessment before treatment
01Review of pregnancy records and ultrasound findingsFirst step
Why
Confirm the indication and exclude important contraindications.
Interpretation and limitations
Check dates, placental location, presentation, growth concerns and relevant maternal conditions. Use ultrasound if presentation or another finding is uncertain. A previous reassuring scan does not override a new clinical concern at induction assessment.
02Abdominal and vaginal assessment
Why
Assess presentation, engagement and cervical readiness before choosing treatment.
Interpretation and limitations
Determine whether the head is stable and well applied to the cervix, then assess the Bishop score with consent. A high or unstable presenting part changes the safety of amniotomy because of cord prolapse risk.
03Baseline cardiotocography and uterine activity
Why
Establish fetal wellbeing before pharmacological induction begins.
Interpretation and limitations
Confirm a normal fetal heart pattern and assess existing contractions before giving medication. An abnormal result requires clinical review and may change the induction or delivery plan rather than simply justify more monitoring during the same treatment.
04Maternal observations and indicated laboratory tests
Why
Identify illness that changes induction safety or urgency.
Interpretation and limitations
Treatment approach
01Choosing the methodMatch treatment to the cervix and riskFirst stepInduction is agreed after assessment confirms that a vaginal birth pathway is appropriate.+
1Explain available methods and their benefits, discomfort, monitoring requirements and risks, then obtain consent for the selected approach.
2For a Bishop score of 6 or less, offer suitable vaginal dinoprostone or low-dose oral misoprostol, checking the product's contraindications and administration instructions.
3Consider a balloon catheter or osmotic cervical dilator when pharmacological methods are unsuitable, including relevant scar or hyperstimulation concerns, or when the patient prefers a mechanical approach.
4For a Bishop score above 6, offer amniotomy and intravenous oxytocin. If the woman chooses to delay oxytocin, explain that labour may take longer and neonatal infection risk may increase.
5
Regimens, contraindications and interactions
Ripens the cervix and stimulates uterine activity when induction is appropriate.
Oral misoprostol, Angusta 25 microgram tablets
The UK SmPC allows 25 micrograms orally every 2 hours or 50 micrograms every 4 hours, to a maximum of 200 micrograms in 24 hours. NICE specifies low-dose 25-microgram oral tablets as an induction option. Wait at least 4 hours after the last Angusta dose before oxytocin.
Use the agreed maternity regimen with fetal and uterine monitoring. Do not continue once labour has started, with hyperstimulation or fetal concern, and check contraindications including previous uterine surgery. The swallowed dose cannot be retrieved if excessive activity develops.
Provides sustained cervical ripening with the ability to remove the drug source.
Dinoprostone 10 mg vaginal delivery system
Insert one 10 mg controlled-release system according to the product instructions; it releases approximately 0.3 mg/hour over 24 hours. Remove after 24 hours, or sooner for the specified clinical removal criteria. The cited system requires at least 30 minutes between removal and oxytocin.
Remove for established regular painful contractions, specified membrane-rupture circumstances, hyperstimulation or fetal concern. PROPESS specifies at least 30 minutes after removal before oxytocin, but the oxytocin SmPC cited in the augmentation chapter specifies six hours after vaginal prostaglandins. Maternity and pharmacy protocols must reconcile the actual products; the 30-minute interval cannot automatically be combined with that oxytocin preparation.
Complications, monitoring and follow-up
Reassess the fetal heart, contraction pattern and maternal symptoms whenever the clinical situation changes, rather than relying solely on the planned drug timetable.
Record each agent, dose, route, insertion or removal time and cumulative exposure so that subsequent staff can safely plan oxytocin.
Outpatient induction is reserved for selected patients without relevant complications after full assessment, with an agreed review and clear instructions for pain, bleeding, membrane rupture, reduced movements or excessive contractions.
Monitor infection risk after membrane rupture, balancing progress, elapsed time and clinical findings rather than using the clock as the only determinant.
After birth, review the induction experience and explain any unplanned changes, including the reason for assisted or caesarean birth.
Special situations
A membrane sweep is a separate choice
A sweep separates membranes from the lower uterine segment during vaginal examination and may reduce the need for formal induction. NICE recommends discussing it after 39+0 weeks; consent should cover discomfort and possible bleeding.
Mechanical does not mean risk free
A balloon avoids direct prostaglandin exposure and is less likely to cause hyperstimulation, but it still requires correct placement, assessment of suitability and a plan for bleeding, discomfort, infection concerns or membrane rupture.
Scar assessment outranks a favourable score
A favourable cervix may make amniotomy feasible, but it does not remove the significance of previous uterine surgery. Discuss rupture risk and the monitoring and operative resources required before choosing induction or augmentation.
Product intervals are not interchangeable
A removable dinoprostone system, dinoprostone gel and oral misoprostol have different administration and subsequent oxytocin instructions. A prescription should name the preparation and record its stop time, not simply state that prostaglandin was given.
Common pitfalls
01
Treating a Bishop score of exactly 6 as belonging to the above-6 amniotomy branch.
02
Repeating an induction dose because the scheduled time has arrived despite frequent contractions.
03
Using a prostaglandin without reviewing previous uterine surgery or product-specific contraindications.
04
Rupturing membranes without assessing a high or mobile presenting part.
05
Calling an initial ripening failure an automatic indication for caesarean birth without reassessment.
06
Describing monitoring after declined induction as a guarantee that later adverse outcomes will be prevented.
Practice
Two practice questions
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Question 1 of 2
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Obstetrics and gynaecologyOriginal SBA
Select the cervical-ripening threshold
A woman agrees to induction at 41 weeks, with intact membranes, no uterine scar and reassuring fetal assessment. The clinician is deciding between a cervical-ripening pathway and amniotomy with oxytocin. What is the highest Bishop score included in NICE's usual pharmacological ripening branch?
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 7 Sept 2026; clinical approval remains outstanding.
Explain why birth is proposed now, the alternatives, likely duration and how induction may affect the birth experience.
A Bishop score of 6 or less usually requires ripening; a score above 6 supports amniotomy with intravenous oxytocin.
NICE offers vaginal dinoprostone or low-dose 25-microgram oral misoprostol for an unfavourable cervix when suitable.
Consider a mechanical method when pharmacological ripening is unsuitable, hyperstimulation risk matters or the patient chooses it.
Previous uterine surgery materially changes risk and method selection; product contraindications must be checked rather than assuming all prostaglandins are interchangeable.
Failure of an initial attempt calls for reassessment and a shared plan, not automatic repetition of the same regimen.
A pathological fetal heart pattern, persistent bradycardia or new reduced fetal movements requires urgent review.
Constant pain between contractions, unusual bleeding or maternal cardiovascular deterioration requires assessment for an obstetric emergency.
A high or mobile presenting part at membrane rupture increases concern for cord prolapse.
Fever, rigors or offensive amniotic fluid requires assessment for infection and may alter the timing and route of birth.
Record relevant observations and obtain blood tests according to the indication, such as hypertension, infection or bleeding. Routine laboratory testing is not a substitute for assessing the patient's condition and the reason birth is being proposed.
Document the planned reassessment, next step and route for obtaining urgent help if symptoms change.
02Treatment in progressReassess before every further interventionA ripening agent or mechanical method has been started and the patient remains under induction care.+
1Monitor maternal condition, contractions and the fetal heart according to the method, product instructions and current risk.
2When contractions begin after dinoprostone or misoprostol, assess fetal wellbeing and uterine activity with CTG; abnormal findings require continuous monitoring and review.
3Stop additional prostaglandin doses when labour is established or excessive activity develops, and remove a retrievable system when its removal criteria are reached.
4Repeat cervical assessment at an interval appropriate to the preparation and clinical response, avoiding unplanned overlap between uterotonic medicines.
5Before amniotomy or oxytocin, reconfirm presentation, fetal wellbeing and the required interval since the preceding drug or delivery-system removal.
03Complication or unsuccessful attemptPause treatment and reconsider the planThere is hyperstimulation, fetal concern or inadequate progress after the planned induction course.+
1EscalationFor excessive activity, stop ongoing uterotonics, remove retrievable medication and obtain urgent fetal and maternal assessment; consider tocolysis and escalation according to the response.
2Investigate persistent pain, bleeding or deterioration for causes beyond drug-related contractions, including abruption, rupture or infection.
3After an unsuccessful induction attempt, reassess the indication, urgency, maternal and fetal condition, cervical findings and the person's experience.
4Discuss an appropriate rest period, expectant management, another attempt or caesarean birth, explaining why some options may be unsuitable in the current circumstances.
5Ensure the agreed decision, review interval and any criteria for urgent birth are understood and documented.
Reduces uterine activity while reversible fetal compromise is addressed.
Acute tocolysis for excessive contractions
NICE fetal-monitoring guidance suggests terbutaline 0.25 mg subcutaneously when a tocolytic is needed for excessive contraction frequency. Give under obstetric supervision after stopping the causative uterotonic and while monitoring maternal and fetal response.
Assess maternal pulse, cardiovascular disease, blood pressure and glucose-related risks. Tocolysis must not delay necessary operative birth when fetal or maternal compromise persists, and repeat treatment needs reassessment rather than automatic scheduling.