13.06.01 Normal labour

Definition

• • Products of conception expelled by the mother

  • Progressive dilatation and effacement of the cervix

  • Painful, regular contractions

Stages of labour

• • Stages

    • First = Onset of true uterine contractions to full dilatation of cervix

    • Second = Full dilatation and rupture of membrane to delivery of foetus

    • Third = Complete expulsion of foetus to complete expulsion of placenta and membranes

  • Latent/active

    • Latent = <4 cm dilated, irregular contractions

    • Active = >4 cm dilated, rapid further dilatation, fast/continuous contractions

Assessment of cervix

• • Dilatation

  • Effacement

  • Consistency

  • Position of foetus

  • Presenting part

Post-partum haemorrhage

• • Primary (<24 hrs)

    • Atonic uterus

    • Retained placental part

    • Tears

  • Secondary (>24 hrs - 6 weeks)

    • RPOC

    • Infection

    • Endometritis

Bishop score

• Interpretation

  • > 8 => Likely to achieve a successful vaginal birth

  • < 7 => Cervical ripening method (prostaglandins)

Indications for induction

• • Post-term

  • Pre-eclampsia

  • Obstructive cholestasis (risk of stillbirth)

  • Diabetes (big baby)

Head position

• • OA = Best

  • ROA/LOA = Fine, but a bit slower as it has to rotate

  • Transverse get stuck

  • OP get stuck (face presentation)

CTG interpretation

Fetal blood sampling

• • pH < 7.2 => Urgent delivery

  • pH 7.2 - 7.25 => Repeat in 30 mins

  • pH 7.25 - 7.3 => Repeat in 60 mins

Notes

• • Braxton-Hicks contractions: Irregular, occur throughout pregnancy, start at first trimester

  • Power, Passage, Passenger

  • Uterine muscle doesn't ever relax - just progressively contracts

  • Oxytoxin to encourage the placenta out (if >30 mins)

• ERCP = Evacuation of retained products of conception

• Station is measured relative to ischial spines (zero = head at spines)

• STAN = ST analysis/T:QRS ratio = Measure of chronic oxygen deprivation