Obstetrics and Gynaecology
Normal Labour
Stages and mechanism of normal labour for MBBS, including the partograph, active management of the third stage, and foetal heart monitoring, mapped to NMC code OG13.
MedNext Academy | 3 min read
Normal Labour
Stages and mechanism of normal labour for MBBS, including the partograph, active management of the third stage, and foetal heart monitoring, mapped to NMC code OG13.
This chapter describes physiological labour: its stages and mechanism, the three Ps, the cardinal movements, and the use of the partograph to track progress. It also covers active management of the third stage to prevent haemorrhage, foetal heart monitoring and interpretation of decelerations, and options for pain relief.
High-yield: Normal Labour
- Labour is regular painful uterine contractions with progressive cervical effacement and dilatation.
- The first stage runs from onset to full dilatation, the second from full dilatation to delivery of the baby, and the third to delivery of the placenta.
- The first stage is divided into a latent phase up to about 4 to 6 centimetres and an active phase thereafter.
- The three Ps of labour are the power (contractions), the passage (pelvis) and the passenger (foetus).
- The cardinal movements of labour are engagement, descent, flexion, internal rotation, extension, restitution, external rotation and expulsion.
- In a normal vertex delivery the occiput is the leading part and delivers by flexion then extension under the pubic symphysis.
- The partograph plots cervical dilatation against time and flags abnormal progress crossing the alert and action lines.
- Active management of the third stage with a uterotonic, controlled cord traction and uterine massage reduces postpartum haemorrhage.
- Oxytocin given after delivery of the anterior shoulder or the baby is the recommended uterotonic for the third stage.
- Signs of placental separation include a gush of blood, lengthening of the cord and the uterus becoming globular and firmer.
- Continuous foetal heart monitoring uses cardiotocography; intermittent auscultation is adequate in low-risk labour.
- Foetal heart rate decelerations are classified as early (head compression), variable (cord compression) or late (uteroplacental insufficiency).
- Late decelerations are the most worrying pattern and suggest foetal hypoxia.
- Non-pharmacological support, opioids and epidural analgesia are options for pain relief in labour, epidural being the most effective.
Stages of labour
- **First stage:** Onset to full dilatation; latent phase then active phase.
- **Second stage:** Full dilatation to delivery of the baby.
- **Third stage:** Delivery of the baby to delivery of the placenta; active management prevents PPH.
- **Partograph:** Plots dilatation over time; alert and action lines flag slow progress.
NMC competencies in this chapter
- **OG13.1:** Definition and mechanism of normal labour
- **OG13.2:** Partograph and interpretation of labour progress
- **OG13.3:** Conduct of normal labour
- **OG13.4:** Pain relief in labour
- **OG13.5:** Foetal monitoring in labour
Frequently Asked Questions
What are the stages of labour?
The first stage runs from onset to full cervical dilatation, the second from full dilatation to birth of the baby, and the third from birth to delivery of the placenta.
What is the partograph used for?
It plots cervical dilatation against time so that slow or obstructed labour is detected early when progress crosses the alert and action lines.
Why is active management of the third stage recommended?
Giving a uterotonic such as oxytocin with controlled cord traction and uterine massage significantly reduces the risk of postpartum haemorrhage.
Which foetal heart deceleration is most concerning?
Late decelerations, which lag behind the contraction and suggest uteroplacental insufficiency and foetal hypoxia, unlike early decelerations from head compression.
Continue reading
MBBSAll Obstetrics and Gynaecology chapters
Continue through the Obstetrics and Gynaecology chapter map.
Continue studying Obstetrics and Gynaecology
Explore clinician-written learning resources, structured revision and practice across the MedNext platform.
Open in the MedNext appSee plans