Key Facts

Prematurity is the single most important cause of neonatal mortality and long-term morbidity. Advances in neonatal intensive care have dramatically improved survival, but the burden of prematurity-related complications remains significant.

Epidemiology

Approximately 8% of births in the UK are preterm (~60,000/year). Prematurity accounts for approximately 75% of neonatal deaths and 50% of long-term neurological disability in childhood. Survival rates: 23 weeks ~30-40%; 24 weeks ~50-60%; 28 weeks ~90%; 32 weeks ~98%.

Aetiology

• Spontaneous preterm labour (~50%): Idiopathic, cervical incompetence, infection, polyhydramnios, multiple pregnancy
• PPROM (Preterm Premature Rupture of Membranes) (~30%): Infection, inflammation
• Medically indicated (~20%): Pre-eclampsia, IUGR, placenta praevia, maternal medical conditions
• Risk factors: Previous preterm birth (strongest risk factor), multiple pregnancy, extremes of maternal age, low BMI, smoking, cervical surgery

Pathophysiology

Preterm infants have immature organ systems:

• Lungs: Surfactant deficiency (produced from ~24 weeks, mature by ~34-36 weeks) → RDS
• Brain: Fragile germinal matrix vasculature → IVH; periventricular white matter vulnerability → PVL
• Gut: Immature mucosal barrier → NEC
• Eyes: Incomplete retinal vascularisation → ROP
• Immune system: Immature → high infection susceptibility
• Temperature regulation: High BSA:weight ratio, minimal subcutaneous fat → hypothermia

Immediate Complications

• RDS: Tachypnoea, grunting, recession, cyanosis within hours of birth
• Hypothermia: Rapid heat loss
• Hypoglycaemia: Poor glycogen stores
• IVH: Usually within first 72 hours; may be asymptomatic or cause sudden deterioration

Short-Term Complications

• NEC: Abdominal distension, bloody stools, pneumatosis (usually after day 7)
• Sepsis: Early and late-onset; non-specific signs
• Patent ductus arteriosus (PDA): Failure to close; heart murmur, wide pulse pressure
• Apnoea of prematurity: Cessation of breathing >20 sec; due to immature respiratory control

Long-Term Complications

• Chronic lung disease (BPD): O2 requirement at 36 weeks corrected; affects ~30% of <28 weeks
• ROP: Screening from 30-31 weeks PMA for babies <32 weeks or <1501g
• Neurodevelopmental delay: Cerebral palsy, learning difficulties, behavioural problems
• Growth: May have poor postnatal growth; later risk of metabolic syndrome

Red Flags

• Sudden deterioration in preterm infant — consider NEC, sepsis, IVH, pneumothorax
• Recurrent apnoeas — may be sign of sepsis, NEC, or worsening lung disease
• Abdominal distension with blood in stool — NEC until proven otherwise
• Desaturations with bradycardia — may need escalation of respiratory support

Bedside

• Continuous monitoring: SpO2, HR, RR, temperature
• Blood glucose: Every 3-6h initially
• Blood gas: Guide respiratory support

Bloods

• FBC, CRP, blood culture: If sepsis suspected
• U&Es, glucose: Fluid and electrolyte management
• Bilirubin: Preterm infants have lower treatment thresholds

Imaging

• CXR: RDS (ground glass, air bronchograms), pneumothorax, PDA
• AXR: NEC (pneumatosis intestinalis, portal venous gas, perforation)
• Cranial USS: Day 1-3 (baseline), day 7, day 28, and 36 weeks CGA — screen for IVH and PVL

Special Tests

• ROP screening: By ophthalmologist from 30-31 weeks PMA for all <32 weeks or <1501g
• Hearing screen: Before discharge
• MRI brain: At term-equivalent age if abnormal USS or high-risk

Antenatal

• Corticosteroids: Betamethasone 12mg IM ×2 doses 24h apart (or dexamethasone) at 24-34 weeks — reduces RDS (NNT 12), IVH, NEC, death
• Magnesium sulphate: If <30 weeks expected — neuroprotection (reduces CP risk ~30%)
• Tocolytics: Nifedipine or atosiban — to delay delivery for steroid administration (48h)
• In-utero transfer: To centre with appropriate level NICU

Delivery Room

• Thermoregulation: Plastic wrap for <28 weeks (do not dry); radiant warmer; hat
• Delayed cord clamping: ≥60 seconds if baby does not require immediate resuscitation
• Respiratory support: CPAP from delivery room for very preterm; intubation and surfactant if needed
• Surfactant: Poractant alfa (Curosurf) 200mg/kg via ETT or LISA (Less Invasive Surfactant Administration)

NICU Care

• Respiratory: CPAP, IPPV, HFOV as needed; caffeine citrate for apnoea of prematurity (20mg/kg loading then 5-10mg/kg OD)
• Nutrition: Breast milk (ideally maternal EBM) via NG tube; TPN if enteral feeds not tolerated
• Infection prevention: Strict hand hygiene, minimal handling, antibiotic stewardship
• Kangaroo care: Skin-to-skin contact — improves thermoregulation, bonding, breastfeeding, and neurodevelopment

Referral Criteria

• All preterm births <34 weeks — neonatal team at delivery
• Extremely preterm (<28 weeks) — delivery at Level 3 NICU
• Surgical NEC — neonatal surgical team
• ROP requiring treatment — ophthalmology (laser/anti-VEGF)

• Survival by gestation: 23wk ~30-40%; 24wk ~50-60%; 26wk ~80%; 28wk ~90%; 32wk ~98%
• Disability-free survival: Improves ~10-15% per additional gestational week
• BPD: Affects ~30% of <28 weeks; most wean off oxygen by 1-2 years
• Neurodevelopmental outcome (<28 weeks): ~20% have significant disability (CP, severe learning difficulty); ~40% have minor difficulties
• ROP: Severe ROP (stage 3+) in ~10% of <28 weeks; treatment prevents blindness in most
• EPICure studies: Landmark UK studies tracking outcomes of extremely preterm infants

Complications of Prematurity by System

IVH Grading (Papile Classification)