Prematurity

Question 1

Definition of prematurity

Answer 1

• <37 weeks gestation
• 7% of all births in UK
• Single biggest cause of neonatal mortality

Question 2

Risk factors for prematurity

Answer 2

• Previous premature delivery
• Social (low BMI, poverty, smoking, alcohol, drugs, domestic abuse)
• Multiple pregnancy (twins, triplets)
• Infection
• Iatrogenic (PET, IUGR)
• APH
• Cervical incompetence (congenital, iatrogenic - cone/LLETZ)

Question 3

Surivival rates

Answer 3

• Poor at 23 weeks but increases rapidly
• Intact survival over 90% by week 30

Question 4

Neonatal problems

Answer 4

• Respiratory distress syndrome
• Intracranial bleeds - periventricular leukomalacia
• Necrotising enterocolitis (NEC)
• Sepsis
• Retinopathy of prematurity
• Patent ductus arteriosus (PDA)
• Hypothermia
• Metabolic (i.e. hyperbilirubinaemia)

Question 5

Diagnosis of prematurity

Answer 5

• Difficult
• 75% of threatened preterm labour deliver at term
• History and examination
• Fetal fibronectin food negative predictive value but poor positive predictive value
  
  • <10ng/ml - 99% chance will not <34 weeks
  • 10-49ng/ml - 92% chance will not <34 weeks
  • 50-199ng/ml - 12% chance will
  • 200-499ng/ml - 33% chance will
  • >500ng/ml - 75% chance will

Question 6

Management of prematurity

Answer 6

• Steroids (betamethasone)
  
  • Promotes maturation of the lungs
  • 50% reduction in neonatal death
• Tocolytics
  
  • B agonists (Ritodrine)
  • CCBs (Nifedipine)
  • NSAIDs (Indomethacin)
  • Oxytocin antagonist (Atosiban)
  • Contraindications include >4cm cervical dilatation, bleeding, infection)
• Cervical length scan - cervical suture?
• Progesterone?