Stages of Labor
Part of Midwifery and Childbirth
Understanding the physiological stages of labor — what is happening, what normal looks like, and how to recognize when a stage is not progressing normally.
Why This Matters
Labor is one of the most powerful physiological events the human body can undergo. It is also a process with clear stages, defined milestones, and predictable patterns — when you know what to expect. A birth attendant who understands the stages of labor can answer the most important questions that arise: Is this labor progressing normally? How much longer is this likely to take? When should I be concerned? When do I need to act?
Historically, one of the greatest killers in obstetrics was prolonged labor — failure of progress that exhausted the mother, compressed the baby, and eventually caused rupture of the uterus. The tragedy was not the complication itself but the lack of a framework for recognizing it in time to intervene. Armed with the knowledge of what constitutes normal progress at each stage, an attendant can identify abnormal progress hours before crisis develops and redirect to a safer outcome.
Labor is not a single event but a progression through three distinct stages, each with its own physiology, its own landmarks, and its own potential complications.
Stage One: Cervical Dilation
The first stage begins with the onset of regular, progressive uterine contractions and ends when the cervix reaches full dilation (10 cm). This is the longest stage of labor and is subdivided into two phases.
The latent phase: Contractions are irregular, mild to moderate, and often 5-20 minutes apart. The cervix effaces (thins and shortens) and begins dilating from its resting state to approximately 5-6 cm. The latent phase can last 6-20 hours in first-time mothers and 2-10 hours in subsequent births.
During the latent phase:
- The mother may be uncomfortable but should be mobile
- She can eat and drink lightly
- Sleep or rest is encouraged if possible
- The birth attendant does not need to be constantly present
Latent phase management:
- Discourage arrival at the delivery location too early — early admission is associated with more interventions
- Encourage upright position and gentle walking — gravity and movement promote descent
- Warm bath or shower provides effective pain relief
- Reassurance that this phase is normal and necessary
The active phase: Contractions become longer, stronger, and more regular — typically 2-4 minutes apart, lasting 60-90 seconds. The cervix dilates from approximately 5-6 cm to 10 cm. In first-time mothers, normal progress is at least 1 cm dilation per hour; in subsequent births, progress is typically faster.
Signs that the active phase has begun:
- Contractions have a clear pattern — coming at regular intervals
- The mother cannot easily talk through contractions
- The mother’s behavior changes — she becomes more focused, more serious
- Cervical assessment confirms 5+ cm dilation
Assessing cervical progress:
Cervical assessment is performed by internal (vaginal) examination. This must be done with clean hands (ideally gloves) after careful handwashing. Each internal examination introduces infection risk — limit to when information gained will change management.
When to examine:
- On admission at the start of active labor
- If there is concern about progress
- When the mother feels urge to push (to confirm full dilation before allowing pushing)
- After rupture of membranes
- In any emergency
What to assess:
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Dilation: How many fingertips can enter the cervical os? Each finger width is approximately 1.5-2 cm.
- 0 cm: closed (fingertip cannot enter)
- 5-6 cm: active phase (3 finger widths)
- 10 cm: fully dilated (no cervical rim palpable)
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Effacement: Is the cervix thick (2-3 cm long) or thin? Effacement precedes dilation; a completely effaced cervix is paper-thin.
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Station: How far is the presenting part from the mid-pelvis (ischial spines)? Spines = 0 station; above the spines is negative (-1, -2, -3 cm); below is positive (+1, +2, +3). Crowning is approximately +5.
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Membranes: Are the membranes intact (bulging through the os) or ruptured (no fluid sac palpable)?
Partogram: A partogram is a graphic record of labor progress — a grid with cervical dilation plotted against time. It provides immediate visual representation of whether progress is normal. The “alert line” represents 1 cm/hour progress. Falling behind the alert line triggers more intensive assessment.
Even without a formal partogram, the principle is: in active labor, minimal acceptable progress is 1 cm dilation per hour in first-time mothers. Less than this for 2+ consecutive hours is abnormal and warrants assessment.
Stage Two: Pushing and Delivery
The second stage begins at full cervical dilation (10 cm) and ends with delivery of the baby. This is the expulsive phase of labor.
Duration: First-time mothers: up to 2 hours of active pushing is normal, potentially longer if the mother has had effective pain relief that blunts the urge to push. Subsequent births: typically 30-60 minutes or less.
Physiology of the second stage: The baby must navigate the birth canal — the bony pelvis and surrounding soft tissues. This requires:
- Descent: the baby moves downward in the pelvis
- Flexion: the chin tucks toward the chest, presenting the smallest head diameter
- Internal rotation: the head rotates as it navigates the curved pelvis
- Extension: the head extends under the pubic bone and delivers
- Restitution: the head rotates back to its natural alignment
- Expulsion: the shoulders and body deliver
Monitoring in the second stage:
- Check fetal heart rate between every 2-3 contractions (every 5 minutes)
- Normal: 110-160 bpm between contractions
- A heart rate that drops below 100 and does not recover within 15-20 seconds after a contraction ends is concerning
- Sustained heart rate above 180 after contractions: also abnormal
- Signs of fetal compromise: thick meconium in the amniotic fluid (in head-first presentations), prolonged heart rate deceleration
Supporting the second stage:
- No fixed duration limit if mother and baby are both doing well
- Encourage position changes — upright positions use gravity, lateral position reduces perineal trauma
- Avoid coached “purple pushing” (forced breath-holding) — allow physiological pushing with contractions
- Provide continuous support — the second stage is exhausting and frightening for many women
Abnormal second stage: No descent of the presenting part after 60 minutes of active pushing (or 30 minutes in a multiparous woman) is abnormal. Possible causes: malposition (occiput posterior — baby facing forward instead of back), cephalopelvic disproportion, poor maternal effort due to exhaustion or inadequate uterine contractions. Assessment: position change, encourage pushing with contractions, consider malposition (internal rotation may need encouragement). If no progress, the baby needs to be delivered urgently by the most skilled available intervention.
Stage Three: Placental Delivery
The third stage begins after delivery of the baby and ends with delivery of the placenta. This is the most dangerous stage for the mother due to hemorrhage risk.
Duration: Normal: placenta delivers within 5-30 minutes of the baby. Delivery before 5 minutes can occur; if the placenta has not delivered by 60 minutes, retained placenta should be considered.
Physiological third stage (expectant management): Allow the placenta to separate and deliver naturally without active intervention. Signs of placental separation:
- Gush of blood from the vagina
- Cord appears to lengthen (placenta descending)
- Uterus becomes globular rather than discoid
- Mother feels renewed urge to push
When signs of separation appear: ask the mother to push. Gravity and mild maternal effort usually deliver the placenta. Do not pull on the cord before separation is confirmed — traction on an unseparated placenta can cause uterine inversion.
Active management of the third stage: Active management (giving an uterotonic drug immediately after delivery, controlled cord traction, uterine massage) reduces postpartum hemorrhage risk significantly and is standard in settings with access to uterotonics.
If oxytocin is available: 10 units intramuscularly immediately after delivery of the baby. This is the single most evidence-based intervention in obstetrics — it reduces the risk of life-threatening postpartum hemorrhage by 60%.
Retained placenta: If the placenta has not delivered by 60 minutes: this is a retained placenta emergency. The uterus cannot contract properly around a retained placenta, and hemorrhage will continue. Management options (in order of least to most invasive):
- Encourage the mother to squat or stand — gravity may complete delivery
- Have the mother breastfeed — oxytocin release may contract the uterus and complete separation
- Bladder drainage — a full bladder prevents uterine contraction; catheterize if possible
- Manual removal — the attendant inserts a gloved hand into the uterus and manually separates and removes the placenta. This is a painful, high-infection-risk procedure requiring clean technique and, ideally, anesthesia. It is also lifesaving when no other option exists.
Fetal Heart Rate Monitoring Without Equipment
The fetoscope (Pinard horn) or any sound-conducting object pressed to the abdomen allows intermittent monitoring of the fetal heart during labor.
How to use a Pinard horn:
- Position the flat (hearing) end against your ear and the open end against the mother’s abdomen
- Apply firm but not painful pressure
- Listen — the fetal heart sounds like a ticking clock, faster than an adult heart
- Count for 60 seconds; alternatively, count for 15 seconds and multiply by 4
Optimal placement: The fetal heart is heard most clearly over the fetal back (confirmed by Leopold’s maneuvers). For a head-down fetus: typically in one of the lower quadrants of the abdomen, just below the umbilicus. For a breech: above the umbilicus.
Interpreting what you hear:
- Normal rate 110-160 bpm: reassuring
- Slow rate (<100) or fast rate (>180) that persists: abnormal
- Heart rate drops with contractions and takes more than 15 seconds to return to baseline after the contraction: worrying (late decelerations)
Documentation: Record the fetal heart rate at each assessment with a notation of when it was taken relative to contractions. This record communicates fetal condition over time.
Understanding the stages of labor is the foundation upon which all specific birth skills are built. A birth attendant who can answer “What stage of labor is she in? Is this normal for that stage? What should happen next?” is equipped to provide genuinely safe attendance at birth.