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Labour - Coggle Diagram

- - - - Latent Phase:
      - Cervical effacement and slow dilation (<4 cm).
      - Mild, irregular contractions.
      - Active Phase:
      - Rapid cervical dilation (>4 cm to 10 cm).
      - Regular, painful contractions (every 2–3 minutes).
      - Typical dilation rate: ~1 cm/hour in nulliparous women.
    - - Passive Phase: Full dilation, descent begins but no urge to push.
        
        Active Phase: Maternal pushing with contractions.
        
        Primigravida: up to 3 hours (4 if epidural).
        
        Multiparous: up to 2 hours (3 if epidural).
        
        Ends with delivery of the baby.
    - - Passive management: Placenta delivered spontaneously within 60 mins.
      - Active management (preferred): Oxytocin given; placenta delivered within 30 mins.
      - Signs of placental separation:
      - Gush of blood
      - Lengthening of umbilical cord
      - Fundus rises and becomes firm (globular uterus)
  - - - Expulsion – Delivery of shoulders (anterior first, then posterior) and body.
      - External Rotation (Restitution) – Head realigns with shoulders.
      - Extension – As head passes under pubic symphysis.
      - Internal Rotation – OT → OA, aligns with maternal pelvic outlet.
      - Flexion – Chin tucks to chest → suboccipitobregmatic diameter (smallest).
      - Descent – Progresses through pelvis.
      - Engagement – Fetal head enters pelvic brim; widest diameter below inlet plane.
  - - - Wider pelvic inlet and outlet
      - Shallow sacral curve
      - Larger subpubic angle (>80°)
      - Shorter ischial spines
      - Pelvic types:
      - Gynecoid (ideal for delivery – round inlet)
      - Anthropoid (oval AP – favourable)
      - Android (heart-shaped – unfavourable)
      - Platypelloid (oval transverse – may hinder descent)
- - - - Causes
        
        Premature rupture of membranes
        
        Previous preterm birth or miscarriage after 14 weeks
        
        Abnormalities in the shape of the womb
        
        Multiple pregnancies (e.g., twins or triplets)
        
        Excess amniotic fluid
        
        Short cervix
        
        Smoking
        
        Previous fertility treatment
        
        Vaginal infections
      - Risk factors
        
        Non-modifiable (Major)
        
        Previous preterm birth (20-40% increased risk depending on number of previous preterm births)
        
        Multiple pregnancies (50% risk)
        
        Uterine and cervical abnormalities
        
        Non-modifiable (Minor)
        
        Teenagers with subsequent pregnancies
        
        Ethnicity (higher in Black women)
        
        Low socioeconomic status
        
        Modifiable
        
        Smoking
        
        Drug abuse
        
        Low BMI (<20)
        
        Short inter-pregnancy intervals
        
        Diagnosis
        
        Transvaginal Ultrasound (Cervical Length):
        
        Measurement of cervical length is used to assess risk. A cervical length of <15mm is associated with preterm labour.
        
        Fetal Fibronectin (fFN) Test:
        
        A glycoprotein found in high concentrations in cervicovaginal secretions, used to predict preterm birth between 22-34 weeks.
        
        Management and Prevention
        
        Maternal Corticosteroids:
        
        To promote fetal lung maturation, reduce respiratory distress syndrome (RDS), and other complications.
        
        Tocolytics:
        
        Drugs like Nifedipine and Atosiban inhibit uterine contractions to delay preterm labour.
        
        Magnesium Sulphate:
        
        Used for neuroprotection in cases of imminent preterm birth.
- - - - Triggered by:
      - Functional progesterone withdrawal (despite unchanged circulating levels)
      - Increased oestrogen promotes expression of:
      - Oxytocin receptors
      - Prostaglandin receptors
      - Gap junctions
      - ↑ Excitability of myometrium
      - ↑ Intracellular Ca²⁺ → Actin-myosin interaction → Contraction