Normal and Abnormal Labour

Normal labour: regular, frequent uterine contractions with cervical changes and descent of the presenting part

Stages of labour

I –        Latent: up to 3-4 cm dilation and effacement (false labour, pre-labour)

Active: 4cm to full dilation → abnormal if <0.5cm/hr over >4hours

II –      Full dilation to delivery → abnormal if no descent over >1hour pushing

III –     Delivery of placenta

IV –     2 hours postpartum (may be up to 6 weeks)

Dystocia – arrest of progression of labour


Assess the the 5 P’s:

  • Power:
    • Strength of contractions (not on monitor, must feel)
    • Must have rest in between ( beware of tachysystole, coupling)
    •  May be augmented with oxytocin
  • Passenger
    • Size
    • Lie: longitudinal/transverse
    • Presentation: face (mentum – anterior can deliver vaginally), brown (frontum), vertex (occiput), transverse (shoulder), breech (sacrum)
    • Position: OA 8.5cm diameter, OP 9cm, brow 13cm
    • Attitude: asynclitism
  • Passage
  • Psyche
  • Pain
    • Reduce stimuli (maternal movement, ARM for decompression)
    • Activate peripheral sensory receptors (water, TENS)
    • Enhance descending inhibitory pathway (hypnosis, music)
    • Narcotics (with antiemetic)
    • Entanox (inhaled N2O)
    • Do not use sedatives/hypnotics
    • Epidural: most effective, does not lengthen 1st stage
    • Pudendal: use in 2nd stage (10cc local under ischial spines)
    • Perineal infiltration

Arrest of 1st stage: amniotomy, oxytocin augmentation, therapeutic rest with analgesia (epidural), C-section

Oxytocin augmentation (drip because of short t1/2 titrated to contractions)

  • Unsatisfactory in 1st or 2nd stage
  • Inadequate uterine contractions
  • After analgesia, rest, amniotomy
  • Prior to operative vaginal delivery to achieve adequate contractions
  • Beware of hyperstimulation

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