The premature newborn infant Ola Didrik Saugstad Department of Pediatric Research Rikshospitalet University Hospital University of Oslo, Norway Student lecture 9th semester

Prematurity GA < 259 days (37 weeks) Norway: 5.6% (1988) and 6.5% (1996) < 1.5 kg 0.7-1.0% (528 = 0.9% in 1996) < 1.0 kg 0.3 % (200 =0.3% in 1996) USA: 7% among caucasians 18% among black

Preterm infants Slight 32-36 weeks Feeding and temperature problems, some have immature lungs Moderate 28-31 weeks Immature lungs, temperature control, feeding problems, apneas Severe < 28 weeks Immature organ systems, intensive care Slight and moderate approx 3000, severe 200 (0.3-0.4%) per year

Terminology Low birth weight < 2.5 kg Very Low Birth Weight < 1.5 kg Extremely Low birth Weight < 1.0 kg Premature < 37 weeks Immature < 28 weeks ELGAN: Extremely Low Gestational Age Newborn < 26 weeks Small for gestational age < 2.5 percentile

General problems in premature infants Feeding: (IV – Gavage) Temperature control: (incubator-heated bed) Respiratory control: apneas, Respiratory support CPAP, Artificial ventilation Immature lungs – lack of surfactant: Oxygen suppl, Respiratory support (CPAP, ventilator) Immature brain: brain hemorrhage and cysts Immunology: risk of infections (antibiotics) Organ injury (Brain, Eye, Lung, Intestine, Skin Long term consequences

Survival 1940: 50% with BW1500 gram survive Birth weight % Survival after 1 year 350-499 g 14 500-799 g 47 750-999 g 76_______________ Medical Birth Registry 1992-96

Survival Gestational age weeks Survival % 21 0-4 22 0-12 23 8-36 21 0-4 22 0-12 23 8-36 24 12-62 25 31-79 26 53-85 NFR’s Consensus report 1999

Sequels From 1979 to 1994 survival among preterm infatns with BW 501-800 gr increased from 20 to 59%. The percentage of children with severe neurosensory injury was however, unchanged (O’Shea 1997)

Injury of ELGANs 1972-1990 < 26 uker < 800 gram Mental retardation 14% 14% Cerebral palsy 12% 8% Blindness 8% 8% Deafness 3% 3% ”Major disability” 22% 24% Survival increased, however rate of injury was constant Lorents JM et al 1998, (meta-analysis including > 4000 children)

Injury of preterm infants Eye ( Retinopathy of prematurity ROP Stage 1-5) Brain injury (Intracranial hemorrhage (grade 1-4) Periventricular leukomalacia PVL). Immature capillaries (plexus Choroides), hemodynamic changes, intrauterine inflammation Pulmonary ( Bronchopulmonary dysplasia - BPD, Chronic lung disease - CLD) Intestinal (necrotizing enterecolitis - NEC)

Development and pathogenesis of ROP

Impact of BPD, Brain Injury & ROP on 18 m Outcome of ELBW Infants Overall probability of a poor outcome @ 18 m (35%) “ A simple count of 3 common neonatal morbidities strongly predicts the risk of later death or disability ” Schmidt B et al. JAMA. March 2003;289:1121-29

School problems A Dutch study showed that > 50% with BW < 1500 gram needed extra support at school No relation between Gestational age and injury Preterm infants have to be followed-up at least till school age because these problems have a late debut. Learning problems picked up around 8 years ADHD Hyperactivity Intellectual problems (arithmetics, solving problems, cognitive functions) Short term memory Coordination problems Behavioral problems (shy, sport performance, sosialise ) Boys> girs Low Socioeconomic conditions

Future challenges Prevent preterm birth Understand relation between intrauterine conditions and postnatal injury Improved nutrition Improved technology New drugs (antioxidants, anti inflammatory, etc) New insight into the needs and the psychological development