Stages of Labour

SWARAJ HOSPITAL & RESEARCH INSTITUTE

BOLANGIR, ODISHA  •  OBSTETRICS & GYNAECOLOGY CLINICAL PATHWAY SERIES

Clinician Reference Infographic

Onset & Stages of Labour — From the First Signs to the Fourth Stage

Normal labour is a physiological process that starts when the fetus, placenta and uterus are ready and unfolds in four stages. The task for the birth attendant is to recognise true labour, monitor at the right intervals, support the woman, and intervene only when progress or safety demands it.

🎯 AT A GLANCE — WHAT IS LABOUR?

Labour is the process by which the fetus, placenta and membranes are expelled from the uterus: regular, painful uterine contractions that produce progressive cervical effacement and dilatation

It is divided into four stages: the first stage (onset to full dilatation, with latent and active phases), the second stage (full dilatation to birth of the baby), the third stage (birth of the baby to delivery of the placenta), and the fourth stage (the first 1–2 hours after delivery)

Pace varies widely. Contemporary data show that normal labour is often slower in early labour and faster later than classic textbook curves — so guidelines now allow more time before labelling labour as abnormal

Good care means three things: recognise true labour, monitor mother and baby at the right intervals, and intervene only when there is a clear reason.

PART 1 · ONSET OF LABOUR — how it starts

🧬 THE PHASES OF PARTURITION

Phase 0 — QuiescenceMost of pregnancy: the myometrium is relaxed under the influence of progesterone, relaxin, nitric oxide and others; the cervix stays firm and closed

Phase 1 — ActivationIn late pregnancy the uterus is prepared: contraction-associated proteins appear (connexin-43 gap junctions, oxytocin and prostaglandin receptors) and the cervix ripens — collagen is remodelled, water and hyaluronan increase

Phase 2 — StimulationLabour: oxytocin and prostaglandins (PGE2, PGF2α) drive coordinated contractions, with progressive effacement and dilatation

Phase 3 — InvolutionAfter delivery: sustained oxytocin-driven contraction expels the placenta and controls bleeding; breastfeeding keeps oxytocin flowing

⚙️ WHAT TRIGGERS LABOUR? — NO SINGLE SWITCH

Fetal signals: maturation of the fetal HPA axis with a cortisol rise, and surfactant protein A from mature lungs, signal readiness for birth

Progesterone withdrawal: in humans this is functional — progesterone receptor changes reduce its quietening effect, even though levels do not fall

Oestrogen, placental CRH, and oxytocin rise; prostaglandin synthesis increases; the myometrium stretches

Inflammatory changes — immune-cell infiltration and cytokines — help the cervix ripen and the uterus contract (see our Immunology guide)

Clinical link: early activation of these same pathways, for example by infection, causes preterm labour; failure to activate them causes post-term pregnancy.

🔔 SIGNS THAT LABOUR IS NEAR

Lightening: the head engages and the uterus drops, easing breathlessness; this may happen 2–4 weeks before labour in first pregnancies, and often only in labour in later ones

Cervical ripening: the cervix softens, shortens and may dilate slightly; a “show” (blood-stained mucus plug) can precede labour by hours or days

Braxton Hicks contractions become more frequent and stronger; backache, loose stools, and an energy surge (“nesting”) are common

Spontaneous rupture of membranes may occur before contractions begin — about 10% of term labours start this way

A show alone is not labour. Advise women to call if the waters break, bleeding is more than a show, contractions become regular, or movements reduce.

🔎 TRUE LABOUR OR FALSE LABOUR?

Feature	True labour	False labour (Braxton Hicks)
Contractions	Regular, with shortening intervals	Irregular; intervals do not shorten
Intensity	Increasing	Mild; unchanging or fading
Pain	Back radiating to the front	Lower abdomen, often groin
Walking, rest, sedation	Not relieved	Often relieved
Cervix	Progressive effacement and dilatation	No change
Show	Common	Absent

PART 2 · STAGES OF LABOUR — from first contraction to fourth stage

📊 THE STAGES AT A GLANCE

Stage	Starts and ends	Typical upper limits
First — latent	Onset of painful contractions to the start of active labour; slow cervical change	Can last up to about 20 h in first labours and 14 h in later ones — not by itself an indication for caesarean
First — active	Rapid dilatation (from 5–6 cm, depending on guideline) to full dilatation, 10 cm	No fixed hourly rate; usually faster than 0.5 cm/h in first labours and quicker in later ones
Second	Full dilatation to birth of the baby	First labours: up to 3 h of active pushing (4 h with epidural); later labours: up to 2 h (3 h with epidural)
Third	Birth of the baby to delivery of the placenta and membranes	30 min with active management; 60 min if physiological
Fourth	First 1–2 hours after delivery	Close observation for haemorrhage and shock

These are upper limits, not targets. Allow more time when mother and baby are well and the labour is progressing — individualise.

📏 WHEN DOES ACTIVE LABOUR START? — GUIDELINES DIFFER

Guideline	Active first stage begins at	Comment
ACOG (2014)	6 cm	Do not diagnose slow progress before 6 cm; allow longer latent phases
WHO (2018)	5 cm	Labour Care Guide; a 1 cm/h rate is not a reliable threshold
NICE (2023)	4 cm	Regular painful contractions and progressive dilatation from 4 cm

Use your unit's protocol consistently, and avoid admitting a woman or starting interventions on the basis of a single threshold

See our Partograph guide for the WHO Labour Care Guide and the classic partograph

🩺 FIRST STAGE — WHAT TO DO

1

Assess on admission: history, maternal pulse, BP, temperature, urine, abdominal palpation, contractions, fetal heart, and a vaginal exam if labour is likely

2

Monitor the fetus: intermittent auscultation after a contraction for at least 1 minute — about every 15–30 minutes in active labour (every 5 minutes in the second stage); use CTG for risk factors

3

Monitor the mother: pulse hourly, BP and temperature every 4 hours, and encourage urination every 2–4 hours

4

Vaginal examinations about every 4 hours, or sooner if there is a concern; record on a partograph or Labour Care Guide

5

Support the woman: a companion of her choice, mobility and upright positions, oral fluids and light food, and pain relief of her choice

⚠️ SLOW PROGRESS — WHEN TO ACT

Latent phase: reassure, support, rest and analgesia; do not rush into oxytocin or caesarean section

Active phase arrest (ACOG): cervix ≥ 6 cm with ruptured membranes and no change for ≥ 4 hours with adequate contractions, or ≥ 6 hours with oxytocin but inadequate contractions

First look for the 3 Ps: power (contractions), passage (pelvis), passenger (size, position); correct dehydration, bladder fullness, and malposition

Treat with amniotomy if appropriate and oxytocin augmentation; reassess after 2–4 hours; consider caesarean for arrest despite adequate contractions (see our Induction & Augmentation and Obstructed Labour guides)

👶 SECOND STAGE — FULL DILATATION TO BIRTH

Passive phase: full dilatation without an urge to push — wait up to 1–2 hours for descent and the urge, especially with an epidural; active phase: maternal pushing with visible descent

Pushing: follow the woman's urge, usually with open-glottis, spontaneous pushing; avoid prolonged breath-holding

Positions: upright, lateral, or all-fours are acceptable; lithotomy is not required

Perineum: warm compresses and a controlled head delivery help; use restrictive episiotomy only for clear indications such as fetal compromise

Delay is defined by time without progress: expect birth within about 3 hours (first labour) or 2 hours (later labour) of active pushing; assess for malposition, inadequate contractions, or pelvic disproportion

🔄 THE CARDINAL MOVEMENTS OF LABOUR

Movement	What happens
1. Engagement	The widest part of the presenting part (biparietal diameter) passes the pelvic inlet
2. Descent	The head moves down through the pelvis, helped by contractions and pushing
3. Flexion	The chin tucks to the chest, presenting the smallest (suboccipitobregmatic) diameter
4. Internal rotation	The occiput turns from transverse to anterior as it meets the pelvic floor
5. Extension	The head extends under the pubic symphysis; the head is born
6. Restitution	The head turns back to its original position, aligned with the shoulders
7. External rotation	The shoulders rotate into the anteroposterior diameter
8. Expulsion	The anterior shoulder, then the posterior shoulder, and then the body are born

🩸 THIRD STAGE — ACTIVE MANAGEMENT

Oxytocin 10 IU IM within one minute of birth of the baby (WHO's first-line); other options are carbetocin and misoprostol where oxytocin is not available

Delayed cord clamping: at least 1 minute (and up to 3) for babies who do not need immediate resuscitation; early skin-to-skin contact

Controlled cord traction after signs of separation (gush of blood, lengthening cord, a firm, rising uterus) with counter-pressure on the uterus; do not pull without these signs

Uterine massage after the placenta is delivered; inspect the placenta and membranes for completeness

Delay: over 30 minutes (60 minutes with physiological management) is a retained placenta — see our Placenta, Cord and Fluid guide

🕐 FOURTH STAGE — THE CRITICAL FIRST HOURS

Observe for at least 1–2 hours: pulse, BP, uterine tone, lochia, and perineal pain, every 15 minutes at first

Most postpartum haemorrhage happens in this period — check the fundus, bladder, and bleeding; call for help at the first concern

Skin-to-skin contact and first breastfeed within the first hour; give vitamin K and ensure the baby is warm

Repair any tear or episiotomy under good analgesia, and record blood loss

Do not transfer the mother out of observation until she is stable, the uterus is firm, and she has passed urine or the bladder is empty

🚨 CALL FOR HELP — DURING ANY STAGE OF LABOUR

Abnormal fetal heart rate (below 110 or above 160 bpm, or persistent decelerations) or thick meconium

Fresh vaginal bleeding, severe abdominal pain, or constant pain with a tense uterus (abruption or rupture)

Maternal fever, tachycardia, or hypotension; BP ≥ 160/110 or headache with visual symptoms

Cord prolapse, shoulder dystocia, non-engaging head in advanced labour, or no progress despite good contractions

🤲 RESPECTFUL, EVIDENCE-BASED CARE

A companion of choice throughout labour and birth improves outcomes and satisfaction

Freedom to move, adopt upright positions, and take oral fluids and light food in low-risk labour

Privacy, respect, and information at every step — with consent for each intervention

Pain relief by choice: non-pharmacological methods, nitrous oxide, opioids, or epidural; offer early and review often

Continuity of care from a trained midwife or doctor improves outcomes

⛔ ROUTINES THAT DO NOT HELP

Routine enema, pubic shaving, or routine amniotomy in normal labour

Routine early oxytocin in the latent phase, or an arbitrary “1 cm per hour” rule

Routine episiotomy, fundal pressure, or enforced lithotomy position

Restricting food and fluids in low-risk women, or strict time limits without assessing the labour as a whole

Repeated vaginal examinations more often than needed — each one adds infection risk

Memory Aid

LABOUR

Six habits for safe, respectful labour care.

L

Latent phase — do not hurry; active labour starts at 4–6 cm, depending on the guideline

A

Assess and record — contractions, cervix, fetal heart, and maternal vitals on a partograph or Labour Care Guide

B

Birth — allow time in the second stage; passive then active; protect the perineum

O

Oxytocin 10 IU IM at birth for the third stage; delayed cord clamping

U

Uterus — massage, check tone, and watch closely through the fourth stage

R

Respect and relief — companion, mobility, fluids, and the pain relief she chooses

Remember: normal labour needs patience, observation and support more than intervention — and the fourth stage is where a quiet labour can still end in haemorrhage.

Swaraj Hospital & Research Institute · Department of Obstetrics & Gynaecology, Bolangir, Odisha

Clinician-facing summary based on WHO (2018), ACOG and NICE guidance; definitions of active labour, time limits and monitoring intervals differ between guidelines — follow local protocol and individualise care.