Normal Labour and Delivery

Normal labour is the physiological process by which the fetus, placenta and membranes are expelled from the uterus after a term or near-term pregnancy. It comprises three distinct clinical stages.

It is established through coordinated uterine contraction, progressive cervical dilation and effacement, and descent of the presenting fetal part through the birth canal.

Understanding the normal progression and expected timeframes of each stage is essential. It allows accurate distinction of normal from abnormal or dysfunctional labour, and guides timely obstetric intervention where required.

Physiology and staging

• The first stage extends from the onset of regular, painful uterine contractions to full cervical dilation (10 centimetres). It has two phases.
  • The latent phase is characterised by slow, gradual cervical dilation and effacement. It is typically the longest and most variable component of labour.
  • The active phase is characterised by more rapid, progressive cervical dilation. In contemporary practice it is generally considered to start at approximately 5 to 6 centimetres, reflecting updated understanding of normal progression compared with historical definitions.
• The second stage extends from full cervical dilation to delivery of the baby. It comprises a passive phase, in which the presenting part descends through the pelvis, often without active maternal pushing. It then comprises an active phase of active maternal expulsive effort.
• Normal second stage duration varies with parity. Nulliparous women generally have a longer expected second stage than multiparous women.
• The third stage extends from delivery of the baby to delivery of the placenta and membranes. It is typically managed actively in contemporary practice, with a uterotonic agent (typically oxytocin) and controlled cord traction. There is clear evidence that active management substantially reduces the risk of postpartum haemorrhage compared with physiological (expectant) management.
• The cardinal movements of labour are the sequential positional adjustments of the fetal head as it navigates the maternal pelvis: engagement, descent, flexion, internal rotation, extension, external rotation (restitution) and expulsion. They reflect the head's adaptation to the changing dimensions of the pelvis at each level of its passage.

• Established labour is characterised by regular, progressively intensifying and increasingly frequent uterine contractions. Progressive cervical change (dilation and effacement) is seen on serial vaginal examination.
• This distinguishes it from the common, often prolonged period of irregular, non-progressive contractions (sometimes termed prelabour or false labour) that frequently precedes true labour.
• The "show" (passage of the cervical mucus plug, often blood-stained) and spontaneous rupture of membranes (with clear or, less commonly, meconium-stained fluid) frequently accompany or precede established labour. Neither is required for the diagnosis. It rests fundamentally on regular, progressive uterine contractions with associated cervical change.
• Progressive descent of the fetal head, with progressive cervical dilation and effacement, is the essential, expected pattern of normal progression. Descent is assessed by abdominal palpation (in fifths palpable above the pelvic brim) and vaginal examination (station, relative to the ischial spines).
• Structured partogram documentation supports systematic, ongoing monitoring of progress throughout labour.
• Regular assessment of maternal wellbeing (vital signs, pain management needs and hydration status) is an essential, ongoing component of intrapartum care. So is continuous or intermittent fetal heart rate monitoring, according to the risk profile of the pregnancy and local protocol.

• Diagnosis of established labour rests on clinical assessment of regular, painful uterine contractions with confirmed cervical change on serial vaginal examination.
• A single examination alone is generally insufficient. Progressive change over time must be demonstrated to distinguish established labour from the common, non-progressive prelabour pattern.
• Structured, systematic use of the partogram supports diagnosis of established labour and, critically, ongoing recognition of normal versus abnormal progression throughout labour. It is a standardised graphical tool plotting cervical dilation, fetal descent and other relevant intrapartum parameters against time.
• Assessment of fetal presentation, position and station, with pelvic assessment where clinically relevant, is an essential component of full intrapartum assessment. It supports appropriate, ongoing management planning throughout labour.

• Ongoing intrapartum care throughout normal labour comprises regular monitoring of maternal and fetal wellbeing. It also supports the woman's preferences on pain management (from non-pharmacological approaches to regional analgesia), position and mobility during labour, and overall birth environment. Care should be supportive, individualised and woman-centred.
• Active management of the third stage is standard, evidence-based practice. It comprises prophylactic administration of a uterotonic agent (typically oxytocin, given intramuscularly or intravenously) at or shortly after delivery of the baby. Controlled cord traction supports delivery of the placenta.
• The approach achieves a clear, substantial reduction in postpartum haemorrhage risk compared with expectant management.
• Careful, ongoing assessment for any deviation from the expected pattern of labour progression, with appropriate, timely management, is an essential, integral component of intrapartum care. Timely recognition and intervention optimise both maternal and neonatal outcome.
• Postpartum assessment after delivery completes management of normal labour and delivery. It includes examination of the placenta and membranes for completeness, assessment of any perineal trauma and its repair where required, and ongoing monitoring for postpartum haemorrhage.
• Clear communication with the woman and her birth partner throughout the process underpins high-quality intrapartum care. Care should be attentive, individualised and respectful, supporting the woman's autonomy and preferences wherever clinically appropriate and safe.