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← Obstetrics and gynaecology indexChapter sections
Purpose and principlesIndications, selection and cautionsAssessment before treatmentTreatment approachRegimens, contraindications and interactionsComplications, monitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Vaginal birth after caesarean

Obstetrics and gynaecology · UK scope · Sources checked 7 Sept 2026 · Clinical review pending

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Possible uterine rupture during labour

An abnormal fetal heart pattern, particularly a prolonged deceleration or bradycardia, may be the earliest sign of rupture. Persistent abdominal pain, new bleeding, loss of station, haematuria or maternal instability increase concern but may be absent.

Action: Call the obstetric emergency team, stop oxytocin if running, begin maternal resuscitation and prepare immediate operative birth when rupture is suspected. Do not wait for a complete symptom triad or diagnostic imaging.

Purpose and principles

Counsel about birth after a previous caesarean, select an appropriate planned pathway and recognise intrapartum findings that require urgent assessment for uterine rupture.

Vaginal birth after caesarean describes an outcome, whereas planned VBAC describes the antenatal intention to labour with the possibility of needing an unplanned operation. This distinction is central to counselling: the advantages of a successful vaginal birth cannot be promised before labour. Successful VBAC generally has the fewest complications, while a labour ending in emergency caesarean carries more morbidity than either a successful vaginal birth or an uncomplicated planned repeat operation. Explain these possible paths in language that supports a realistic choice rather than presenting success or surgery as a personal achievement or failure.

A planned repeat caesarean avoids most labour-related scar risk but introduces operative recovery and contributes another uterine scar, with implications for subsequent placentation and abdominal surgery. The previous experience, indication for the original operation, likelihood of vaginal success, medical conditions and future pregnancy intentions all matter. Someone whose first caesarean followed a non-recurring problem such as breech may have different prospects from someone with repeated labour arrest, but neither history can predict an individual outcome with certainty. The final plan should include what happens if labour begins earlier than expected or pregnancy continues beyond the agreed review point.

Indications, selection and cautions

Reconstruct the previous operation

Review the operation note for incision type, extensions, complications and any specific advice. Ask whether labour occurred and why caesarean became necessary. A transverse skin incision does not prove a lower-segment uterine incision, and uncertainty should lead to records review and senior assessment rather than an assumed low-risk scar.

Assess current suitability

The usual candidate has one previous lower-segment incision, a singleton cephalic fetus and no independent contraindication to vaginal birth. Prior uterine rupture and a classical incision contraindicate planned VBAC. Complicated scars and other uterine operations require individual review by a senior obstetrician with surgical details.

Estimate likely vaginal success

Previous vaginal birth, particularly previous VBAC, strongly predicts success. Spontaneous labour and a non-recurring original indication are favourable features. Discuss factors such as induction, fetal size concerns and previous dystocia as influences on probability, without treating a prediction score as permission that a person must earn.

Identify circumstances needing specialist discussion

Two or more previous lower-segment caesareans do not impose an automatic universal prohibition. RCOG allows consideration after senior counselling in a centre with suitable expertise and immediate surgery. Multiple pregnancy, a suspected large baby, preterm birth or additional maternal disease also require a more individual discussion than a standard uncomplicated-term estimate.

Red flags requiring action

  • A sudden persistent fetal bradycardia during labour with a uterine scar requires urgent assessment for rupture and other acute events.

Assessment before treatment

  1. 01
    Previous obstetric and operative recordsFirst step
    Why
    Identify scar characteristics, prior complications and the reason for the earlier caesarean.
    Interpretation and limitations
    The uterine operation note is more informative than the external scar or a brief discharge label. Obtain missing information early enough to support shared planning. A previous successful VBAC is reassuring history but does not remove the need to assess the current pregnancy.
  2. 02
    Antenatal ultrasound and placental assessment
    Why
    Check fetal presentation and growth and identify placental concerns when clinically indicated.
    Interpretation and limitations
    A low placenta over a uterine scar raises concern for accreta spectrum and changes the pathway. Ultrasound weight estimates have uncertainty and cannot establish pelvic adequacy. Consider the whole pregnancy rather than making the route decision from a single estimated weight.
  3. 03
    Admission maternal and fetal assessment
    Why
    Establish labour status, current wellbeing and any reason to alter the planned route.
    Interpretation and limitations
    Review contractions, pain, bleeding, membranes, observations and cervical progress with consent. Use continuous CTG from regular contractions during planned VBAC. An antenatally suitable plan must be reconsidered if the current presentation suggests compromise.
  4. 04
    Blood group, antibody status and blood count

Treatment approach

01Antenatal decisionCompare realistic birth pathwaysFirst stepA person with a previous caesarean is considering how to give birth again.+
  1. 1Review previous surgery and current pregnancy factors, then discuss the likely benefits, risks and recovery of planned VBAC and planned repeat caesarean.
  2. 2Explain approximate success and rupture figures with their limitations, giving particular weight to prior vaginal births, the original indication and any need for induction.
  3. 3Agree the planned setting and route, record the person's priorities and provide accessible written information that can be revisited.
  4. 4Document contingencies for early labour, membrane rupture and pregnancy beyond the agreed review point; if repeat caesarean is selected, normally arrange it from 39 weeks unless earlier birth is indicated.
02Labour careMonitor progress with access to immediate surgeryRegular labour begins in someone planning vaginal birth after caesarean.

Regimens, contraindications and interactions

May improve inadequate uterine activity in selected VBAC labour after obstruction and fetal compromise have been assessed.

Oxytocin when augmentation is agreed

Use only the consultant-agreed, pump-controlled intravenous regimen for labour with a uterine scar, documenting starting rate, increments, maximum rate and stopping criteria rather than importing a routine unscarred-uterus prescription.

Induction and augmentation increase rupture risk. Continuous CTG and contraction assessment are essential; reduce or stop stimulation for excessive contractions and stop immediately for suspected rupture or significant fetal deterioration. The exact product and local scar-specific protocol require reconciliation.

Provides effective pain relief and can support anaesthesia if operative birth becomes necessary.

Epidural labour analgesia

The anaesthetist selects and titrates the local anaesthetic and opioid regimen to provide effective labour analgesia, considering previous doses and the patient's medical and haemodynamic status.

Epidural analgesia is not contraindicated by planned VBAC. New breakthrough pain, focal pain between contractions or an escalating top-up requirement requires obstetric assessment as well as checking block function; do not assume every new pain represents a technical failure.

Complications, monitoring and follow-up

  • Record maternal pulse, blood pressure, bleeding, abdominal symptoms and labour progress with a frequency appropriate to the scar and developing risks; CTG surveillance complements maternal assessment.
  • Review the whole fetal trace and contraction pattern regularly, and ensure handovers include scar type, any augmentation and the agreed thresholds for senior review.
  • After vaginal birth, assess blood loss and recovery normally but investigate unexpected abdominal pain, haemodynamic changes or ongoing bleeding for occult complications.
  • After an unplanned caesarean, explain the operative findings and whether scar dehiscence or rupture occurred, because these have different implications for future birth counselling.
  • Provide a written account of the outcome and support questions about the experience, avoiding language that implies an unplanned operation is a personal failure.

Special situations

A rupture is not always painful

Fetal heart abnormalities are the most consistent warning feature, and an intact pain response cannot be relied upon to exclude rupture. Conversely, pain is common in labour and does not diagnose it. Evaluate combinations, changes and the clinical trajectory promptly.

Scar thickness has limits

Studies associate lower uterine segment thickness with scar defects, but RCOG does not identify a universally usable threshold for clinical decisions. A single measurement should not be presented as a definitive clearance test or a guarantee that rupture cannot occur.

The next pregnancy also matters

Successful VBAC avoids another surgical scar, while repeat caesarean may offer predictability that a person values greatly. Discuss future accreta and surgical complexity in proportion to the intended family size without pressuring someone to accept a route they do not prefer.

Unexpected labour needs a fresh decision

A person booked for repeat caesarean may present in advanced labour, while someone planning VBAC may develop a new contraindication. Review the current stage, wellbeing and preference with an experienced obstetrician rather than following the antenatal label mechanically.

Common pitfalls

  1. 01

    Assuming a low transverse abdominal scar establishes the type of incision made in the uterus.

  2. 02

    Quoting the benefits of successful VBAC without discussing the possibility and consequences of an unplanned caesarean.

  3. 03

    Treating a previous vaginal birth as proof that rupture cannot occur during the current labour.

  4. 04

    Delaying review of a prolonged fetal deceleration while waiting for scar pain, bleeding and shock to appear together.

  5. 05

    Using prostaglandin induction or a routine oxytocin schedule without considering product restrictions and a senior scar-specific plan.

  6. 06

    Banning epidural analgesia because it is thought to prevent recognition of every uterine rupture.

Practice

Two practice questions

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Obstetrics and gynaecologyOriginal SBA

Personalise the success discussion

A woman with one previous uncomplicated lower-segment caesarean subsequently had a vaginal birth. She now has a healthy singleton cephalic pregnancy and asks about planned VBAC. Which approximate success estimate best reflects RCOG counselling for someone with a previous vaginal birth?

Choose one answer, then submit
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Sources and review status5 sources · checked 7 Sept 2026 · clinical review pending+
Sources

Sources and review status

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.

  • RCOG Green-top 45 Birth after previous caesarean
  • RCOG Patient information on birth after caesarean
  • NICE NG192 Caesarean birth and previous caesarean
  • NICE NG207 Induction after previous caesarean
  • NICE NG229 Fetal monitoring during labour

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom

Key points

  • Most people with one previous lower-segment caesarean and an uncomplicated singleton cephalic pregnancy can consider planned vaginal birth.
  • Establish the uterine incision and previous operative findings from records; the abdominal skin scar does not identify the uterine scar.
  • RCOG quotes planned vaginal birth success around 72–75%, rising to approximately 85–90% after a previous vaginal birth.
  • Discuss an approximate uterine rupture risk of one in 200 with planned vaginal birth, explaining that individual circumstances modify this estimate.
  • Plan labour where continuous fetal monitoring, immediate caesarean birth, blood transfusion and advanced neonatal resuscitation are available.
  • Previous classical incision or uterine rupture, and other contraindications to vaginal birth, usually require an alternative planned route.
  • Induction or augmentation changes the risk discussion and requires a senior, explicitly documented plan for method, monitoring and progress.
  • Severe pain between contractions, unexpected breakthrough pain or a rapidly increasing analgesic requirement needs obstetric reassessment.
  • Loss of fetal station, haematuria or new vaginal bleeding may indicate scar disruption even before major maternal haemodynamic changes.
  • Tachycardia, hypotension or collapse can reflect concealed intra-abdominal bleeding and should not be reassured by limited visible vaginal loss.
    • Why
    Prepare for possible operative birth and assess anaemia or transfusion complications.
    Interpretation and limitations
    Establish intravenous access and ensure appropriate blood sampling according to the unit's labour pathway. Major haemorrhage requires urgent blood provision and resuscitation; treatment should not wait for routine laboratory results when the clinical picture indicates rupture.
    +
    1. 1Assess the mother and fetus promptly, confirm the scar history and birth plan, obtain intravenous access and ensure the relevant teams know the patient is labouring.
    2. 2Use continuous CTG with regular maternal observations and assessment of contractions, pain and cervical progress in a unit capable of immediate caesarean and advanced neonatal support.
    3. 3Offer appropriate analgesia, including epidural if desired, while investigating new pain or an unexpectedly increasing requirement.
    4. 4EscalationEscalate delay or fetal abnormalities early, with explicit senior decisions about continued labour, augmentation, assisted birth or caesarean according to the actual findings.
    03Induction or delayReassess the balance before stimulating labourBirth needs initiating or labour progress is inadequate in a patient with a caesarean scar.+
    1. 1AlternativeAsk a senior obstetrician to reconsider vaginal suitability, the reason birth is needed and the alternative of repeat caesarean.
    2. 2Discuss that induced or augmented VBAC labour carries around two to three times the rupture risk and roughly one and a half times the caesarean risk compared with spontaneous VBAC labour in RCOG counselling data.
    3. 3Select the method carefully: mechanical induction can be considered, while NICE notes that dinoprostone and misoprostol product authorisations contraindicate their use for induction in a uterine scar.
    4. 4If oxytocin augmentation is agreed, prescribe a specific cautious regimen and monitoring plan, with recorded examination intervals and criteria for stopping the vaginal-birth attempt.
    04Acute concernRespond to suspected scar ruptureFetal deterioration or maternal findings raise concern that the uterine scar has disrupted.+
    1. 1Summon senior obstetric, anaesthetic, theatre, neonatal and haemorrhage support while immediately stopping any oxytocin infusion.
    2. 2Assess airway, breathing and circulation, obtain large-bore access and begin resuscitation and blood preparation according to the clinical state.
    3. 3Prepare urgent laparotomy and birth when rupture is suspected; imaging and a complete set of classical symptoms are not prerequisites.
    4. 4Communicate findings and treatment continuously, then arrange postoperative explanation, psychological support and clear advice about future pregnancy.