Long-term outcomes of
Prematurity
Gehan Roberts
Centre for Community Child Health, RCH
Murdoch Childrens Research Institute
Department of Paediatrics, University of Melbourne
Contents
• Introduction
– Definition
– Prevalence
• History
• Outcome studies
– Changes over time
• Intervention studies
• Future directions
Definition
Term: >=37
• Preterm <37/40
– Late preterm: 33 to 36+6
– Very preterm: 28 to 32+6
– Extremely preterm: <28
• Alternative classifications based on birthweight
– LBW <2500g
– VLBW <1500g
– ELBW <1000g
Prevalence
• Late preterm ~7%
• Very preterm ~1-2%
• Victoria: 60-75,000 births p. year
– About 5000 preterm
– About 750 very preterm
History
• Victorian Infant Collaborative Study
– ELBW infants (500-999g)
– + <28/40 after 1991
• 5 cohorts
– 1979-80, 1985-87, 1991-92, 1997, 2005
ELBW infants in Victoria
1979-80
1985-87
1991-92
1997
2005
n=351 (3.03/1000 livebirths)
n=560 (3.06/1000 livebirths)
n=429 (3.29/1000 livebirths)
n=233 (3.77/1000 livebirths)
n=257 (3.88/1000 livebirths)
175/yr
187/yr
215/yr
233/yr
257/yr
Traditional Outcomes
• Survival
– Discharge
– 2 years
• Neurological disability
– Deafness
– Blindness
– Cerebral Palsy
Survival
% survival
100
80
60
500-999
40
20
0
79-80 85-87 91-92 1997 2005
Era
Survival
% survival
100
80
60
500-749
750-999
40
20
0
79-80 85-87 91-92 1997 2005
Era
Cerebral Palsy
% CP
20
15
10
5
0
79-80
85-87
91-92
Era
1997
2005
Blindness
% blind
10
8
6
4
2
0
79-80
85-87
91-92
Era
1997
2005
Deafness
% deaf
10
8
6
4
2
0
79-80
85-87
91-92
Era
1997
2005
Developmental outcomes
• Increasingly important
– More very tiny babies surviving to school-age and
adulthood
• Need to compare outcomes against a control
group
– How are they doing compared with same-age
peers?
Cognitive Delay: age 2
nil
% survivors
mild
moderate
severe
100%
80%
60%
40%
20%
0%
79-80
85-87
91-92
Era
1997
2005
What about older children?
• Cognitive skills
– IQ
– Language
– Attention, Executive function
• Educational outcomes
• Behavioural and Psychological outcomes
– Autism, ADHD, mood problems
School readiness
• ‘School readiness’
– Term 1st used a century ago
– Assessment framework for understanding profiles
of strengths and vulnerabilities of the preschoolage child
• Very preterm children are at high risk of
difficulties in school
– 50% have academic/ behavioural difficulties
• Understanding readiness to learn
– potential to aid successful transition into school
Definition
• Three key attributes
– Children who are ready to learn
– Schools that are ready for children
– Parents and communities who support the child’s
development.
• Readiness to learn is further divided into 5 skill areas
– 1) Health and physical development
– 2) Emotional well-being and social competence
– 3) Approaches to learning
– 4) Communication skills
– 5) Cognitive skills and general knowledge.
– Copple, National Educational Goals Panel, 1997
Cumulative number of areas of
difficulty
80
70
Proportion
60
50
VPT
40
Control
30
20
10
0
01
12
23
34
45
Number of Domains
56
Meta-Analysis of Neurobehavioral
Outcomes in Very Preterm Children.
• Pooled results from 14 studies
– >4000 preterm and >3000 term children
• Academic outcomes
– 0.6 SD lower on mathematics
– 04 SD lower on reading
• Behavior problem
– 0.4 SD higher overall, 0.6 SD higher for attention problems
• Executive function
– 0.4 SD lower for working memory
• Aarnoudse-Moens, Pediatrics, 2009
Relationship between gestation and IQ
‘Preterm and low birth weight babies’, Dieter Wolke,
Sage Handbook of Developmental Disorders
Relationship between gestation and IQ
‘Preterm and low birth weight babies’, Dieter Wolke,
Sage Handbook of Developmental Disorders
‘Preterm behavioural phenotype’:
increased inattention, anxiety, social difficulties
-Johnson et al, Ped Res, 2011
Prevalence of psychiatric
disorders at 11 y of age in
a population-based cohort
219 EPT (26 wk) children
(BLUE)
152 term-born classmates
(RED)
-UK EPICure Study
Swedish national
cohort of 1 180 616
children born between
1987 and 2000,
followed up for ADHD
medication
in 2006 at the age of 6
to 19 years
Preterm personality profile
•Compared with term controls, VLBW adults (age 21 y)
are…
•More conscientious
•Agreeable
•Less open to new experiences
•Less hostile or impulsive
•Less assertive
•Independent of age, gender, school achievement, parental
education, maternal health
•Pesonen et. al, Helsinki Study of VLBW adults, J Ch Psychol. Pstychiatr. 2008
Birth Weight in Relation to Leisure Time Physical Activity
in Adolescence and Adulthood: Meta-Analysis of Results
from 13 Nordic Cohorts. Andersen et al. PLoS ONE, 2009
Meta-analysis of logistic
regressions of leisure time
physical activity as a
function of birth weight.
The points depict
log(OR) and corresponding
95% confidence intervals
Respiratory health
Preterm children, compared with term controls, have…
•More hospital readmissions with URI/ LRIs
•More airway obstruction
•Poorer exercise tolerance
……in childhood, adolescence and early adulthood.
•This has not been affected by the introduction of
Surfactant
•Smoking probably contributes to worsening of these
outcomes
•Those who had BPD as neonates do worse than those
who did not.
Quality of life
•Young adults born preterm:
•report no differences in the self-reported
quality of life despite recognition of their
disabilities
•‘the disability paradox’
•ELBW and control adolescents and their parents
provide higher ratings of health-related quality of
life for severely disabling hypothetical health states
than did health professionals.
•Saigal, Lancet, 2008
Future directions
• Intervention
– Long-term follow-up of promising NICU
interventions
• Caffeine, DHA, antenatal Magnesium
– Interventions targeted to areas of vulnerability
• Working memory
• Social-emotional development
– Novel intervention delivery
• Web-based?
25 weeks
26 weeks
30 weeks
32 weeks
34 weeks
40 weeks