Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Diagnosis and stages of labour
Obstetrics and gynaecology · UK scope · Sources checked 7 Sept 2026 · Clinical review pending
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Symptoms that require urgent assessment
Heavy vaginal bleeding, persistent pain between contractions, collapse, abnormal fetal heart rate or a visible or palpable cord are not explained by uncomplicated labour. Do not wait for a cervical dilatation threshold before escalating.
Action: Call for obstetric and midwifery assistance, assess maternal airway, breathing and circulation, and evaluate the fetal heart promptly. Manage the suspected emergency, arrange transfer when necessary and avoid routine vaginal examination in unexplained bleeding until placental location and the clinical situation have been assessed.
Overview
Distinguish early labour from established progress, assess maternal and fetal wellbeing, and recognise when the stage or course requires a different management plan.
Labour is a physiological process in which uterine activity, cervical change and fetal descent eventually lead to birth. Its boundaries are clinically useful but are not all observed at a single instant. Someone may describe painful contractions for many hours before established labour, while another progresses rapidly with relatively little warning. An assessment should explain what is known, what remains uncertain and what would change the plan. It should not reduce a complex experience to whether the cervix has reached a particular number.
Staging creates a shared language for recording progress and planning care. During the first stage the cervix becomes fully dilated; during the second stage the baby descends and is born; during the third stage the placenta separates and is delivered. The expected rate of change depends on parity, analgesia, fetal position and the clinical picture. Support, food and fluid advice, pain relief and repeated risk assessment remain important even when an examination shows that established labour has not yet begun.
Key points
Practice
Two practice questions
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Obstetrics and gynaecologyOriginal SBA
Identify the established-labour threshold
A woman at term is assessed for regular painful contractions. Two examinations demonstrate progressive cervical dilatation, and maternal and fetal findings are reassuring. From which cervical dilatation does NICE define established first-stage labour when these features are present?
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.
Labour is diagnosed from the pattern of contractions and cervical change, alongside the maternal and fetal assessment.
NICE defines established first-stage labour as regular contractions with progressive cervical dilatation from 4 cm.
The latent phase may be intermittent and includes cervical softening, effacement and early dilatation; its duration varies widely.
The second stage begins at full dilatation and has passive and active components that should be recorded separately.
The third stage runs from birth of the baby to delivery of the placenta and membranes.
Pain intensity alone does not measure dilatation, progress or the need for obstetric intervention.
Consent, privacy, explanation and the person's wishes apply to every vaginal examination, including repeat assessments.
Aetiology
01
Physiological onset at term
Maternal, fetal and placental signalling contributes to cervical remodelling and coordinated uterine contractions. The exact onset varies, and painful intermittent activity may precede sustained progressive labour.
02
Induced or accelerated labour
Cervical ripening, amniotomy and oxytocin can initiate or strengthen the labour process for clinical reasons. The intervention and any underlying indication influence monitoring and risk assessment.
Pathophysiology
1
Cervical remodelling
The cervix softens, shortens and dilates as tissue structure changes and contractions act on the presenting part. Early changes can occur intermittently before established progressive dilatation is evident.
2
Descent and rotation
Uterine contractions and maternal expulsive effort move the fetus through the pelvis. Fetal position, pelvic relationships and soft tissues influence rotation and descent, particularly after full cervical dilatation.
3
Placental separation
After birth, uterine contraction reduces the placental bed and supports separation of the placenta. Sustained myometrial contraction also compresses vessels, limiting blood loss from the implantation site.
Clinical features and red flags
History at first contact
Ask about contraction onset, frequency and duration, coping and analgesia needs, membrane rupture, bleeding and fetal movement. Establish gestation, parity, previous rapid or complicated births, antenatal concerns and the agreed birth setting. A telephone assessment should identify urgency and whether face-to-face care is needed.
Contractions and cervical change
Regular painful contractions with progressive dilatation from 4 cm meet the NICE established first-stage definition. A single examination may not demonstrate progression. Braxton Hicks contractions or a latent phase can be painful without established dilatation, so explain uncertainty without dismissing symptoms.
Passive and active second stage
Full cervical dilatation before involuntary or active pushing is the passive second stage. The active phase begins when the baby is visible or there is involuntary or active pushing with full dilatation. Epidural analgesia may reduce the urge to push and permit a planned passive interval.
Placental separation and the third stage
After the baby is born, observe uterine tone, blood loss and signs that the placenta has separated. Document whether management is active or physiological, because the threshold for a prolonged third stage differs. Ongoing heavy bleeding requires action immediately rather than waiting for either time threshold.
Red flags requiring action
Fresh bleeding greater than an ordinary blood-stained show requires prompt obstetric assessment.
Reduced fetal movements, a persistent fetal heart abnormality or thick meconium requires reassessment of fetal risk.
Investigations
01Maternal observations and abdominal assessmentFirst step
Why
Assess current wellbeing and establish the obstetric context.
Interpretation and limitations
Measure pulse, blood pressure, temperature and respiratory rate as indicated, and assess contractions, lie, presentation and engagement. Symptoms and abnormal observations may change the appropriate place of care even before labour is established.
02Fetal heart assessment
Why
Identify fetal concerns and choose appropriate ongoing monitoring.
Interpretation and limitations
Assess the fetal heart and distinguish it from the maternal pulse. Intermittent auscultation is suitable when risk remains low; antenatal or developing intrapartum risk factors may indicate continuous cardiotocography. A routine admission CTG is not required for every low-risk patient.
03Vaginal examination with consent
Why
Assess the cervix and presenting part when clinically useful.
Interpretation and limitations
Explain the reason, obtain consent and assess dilatation, effacement, membranes, position, station and caput or moulding where relevant. Offer four-hourly examinations during uncomplicated established first stage, or earlier for clinical indications or the person's wishes; avoid repeated examinations without a clear purpose.
04Assessment of possible membrane rupture
Why
Clarify fluid loss and identify infection or cord-related risk.
Differential diagnosis
01
Latent or preparatory contractions
Painful or regular uterine activity can occur without established progressive cervical change. The diagnosis requires context and reassessment, while coping needs and warning symptoms still deserve clinical attention.
02
Prelabour membrane rupture
Fluid loss may precede contractions and does not itself establish labour. Timing, gestation, infection risk and fetal findings determine whether observation or an induction pathway is appropriate.
03
Obstetric or abdominal pathology
Persistent pain, significant bleeding, fever or maternal instability can indicate pathology rather than uncomplicated contractions. Placental abruption, infection and non-obstetric abdominal disease require targeted assessment.
Management
01Early presentationSupport the latent phaseFirst stepContractions are present but established first-stage labour has not been demonstrated.+
1Undertake a maternal and fetal assessment, review risk factors and provide a clear explanation of the findings and uncertainty.
2Offer emotional support, appropriate analgesia and practical advice on rest, comfortable movement and drinking to thirst.
3Discuss home or planned birth-setting care according to clinical suitability, coping, travel, support and the person's preference; do not send someone away solely because dilatation is below 4 cm.
4Give explicit contact instructions for increasing pain, inability to cope, bleeding, reduced movements, membrane rupture or other new concerns.
02First and second stagesFollow progress with repeated assessmentLabour is established or full cervical dilatation has been identified.+
Complications
01
Delay and maternal exhaustion
Ineffective contractions, malposition or other factors can prolong labour and reduce coping. Assessment should distinguish physiological variation from a course requiring augmentation, assisted birth or caesarean delivery.
02
Fetal compromise
Developing hypoxia or another fetal problem may first appear as a heart-rate abnormality. Monitoring and repeated risk assessment allow escalation before the stage or duration alone would suggest intervention.
03
Bleeding and retained placenta
Failure of placental delivery, inadequate uterine contraction or genital tract trauma can cause postpartum haemorrhage. Maternal condition and blood loss determine urgency independently of routine third-stage time limits.
Monitoring and follow-up
In uncomplicated established first stage, document contraction frequency half-hourly, maternal pulse hourly, and temperature, blood pressure and respiratory rate four-hourly, increasing observations when concerns arise.
Continue fetal monitoring at the frequency and method appropriate to the current risk and stage; reassess whenever new risk factors appear.
Monitor bladder function, oral intake and intravenous fluids where used; excessive drinking can contribute to maternal hyponatraemia.
After birth, monitor uterine tone, vaginal loss and maternal observations while supporting skin-to-skin contact and initial feeding when clinically appropriate.
Special situations
Progress is more than dilatation
Rotation and descent provide valuable information, particularly in the second stage. Two examinations with similar dilatation do not have identical significance if the presenting part, contraction pattern or maternal and fetal condition have changed.
Expected duration differs from review timing
Birth usually occurs within three hours of active second stage in nulliparous women and two hours in multiparous women, but senior review is recommended earlier when birth is not imminent. An expected duration is not a guarantee of safety.
Hydration should follow need
Encourage drinking to thirst rather than prescribing excessive oral intake to accelerate labour. Oxytocin and pregnancy physiology reduce the capacity to excrete free water, so both oral and intravenous intake may matter when fluid balance becomes positive.
Consent remains continuous
A person may agree to one vaginal examination and decline the next. Explain how an examination could affect decisions, offer alternatives where possible and respect withdrawal of consent while continuing supportive clinical assessment.
Common pitfalls
01
Equating severe pain with advanced cervical dilatation or using mild pain to exclude labour.
02
Treating every slow latent phase as established first-stage dystocia.
03
Waiting for a scheduled examination despite new bleeding, persistent pain or fetal concern.
04
Recording full dilatation without distinguishing the start of active pushing.
05
Continuing physiological third-stage management despite substantial bleeding or an undelivered placenta beyond an hour.
Constant severe abdominal pain, uterine tenderness or maternal instability requires urgent evaluation for an obstetric complication.
Fever, offensive fluid or worsening maternal tachycardia raises concern for infection.
Symptoms of labour before 37 weeks require the preterm labour pathway rather than routine term reassurance.
Interpretation and limitations
Record the timing, colour and odour of fluid and review fetal movements. If rupture is uncertain, a speculum assessment may help. Avoid digital examination in suspected prelabour rupture without contractions because it can increase infection risk without improving the immediate plan.
1Provide one-to-one midwifery care in established labour and agree the monitoring and pain-relief plan with the woman.
2Document contractions, maternal observations and fetal wellbeing, offering examinations at appropriate intervals and considering the whole pattern of cervical change and descent.
3At full dilatation, distinguish passive from active second stage. With an epidural, pushing may be delayed by one hour in multiparous women and up to two hours in nulliparous women unless there is an urge to push or the head is visible.
4Reassess rotation, descent, contractions and wellbeing during active pushing. If birth is not imminent after two hours of pushing in a nulliparous woman or one hour in a multiparous woman, obtain senior review rather than treating the eventual expected duration as a reason to postpone assessment.
5EscalationEscalate earlier for absent progress, abnormal fetal findings, maternal deterioration or concern about obstruction.
03After the baby is bornManage and observe the third stageBirth has occurred and the placenta and membranes remain undelivered.+
1Discuss and document active or physiological management, remembering that active management reduces postpartum haemorrhage risk.
2With active management, give the agreed prophylactic uterotonic and use controlled cord traction only after signs of placental separation and appropriate uterine support.
3Do not clamp the cord before one minute unless there is a specific concern requiring earlier action; document clamping time and the reason for any deviation.
4Diagnose a prolonged third stage after 30 minutes with active management or 60 minutes with physiological management, while responding immediately to abnormal bleeding at any time.
5After placental delivery, assess completeness, uterine tone, blood loss and maternal condition, and examine for trauma with explanation, consent and adequate analgesia.
Key medicines and prescribing safety1 treatment · regimens, roles and cautions+
Promotes uterine contraction to reduce bleeding after birth.
Oxytocin for active third-stage management
Following vaginal birth, NICE includes oxytocin 10 units intramuscularly or 5 units intravenously as prophylactic options. Where intravenous oxytocin is used after oxytocin in labour, give it slowly over 3–5 minutes according to the obstetric plan.
This prophylactic dose is distinct from a titrated augmentation infusion. Consider the complete haemorrhage-risk and cardiac assessment; intravenous administration can cause cardiovascular effects, and oxytocin with ergometrine is unsuitable in some hypertensive or cardiac conditions.