Prematurity
Class
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Define prematurity.
What factors predict the survival of premature infants
How can prematurity be treated?
What factors affect disability in the survivors? What types of disability and
other outcomes are likely in survivors?
How are mortality and morbidity rates of premature infants changing?
If a baby is born 8 weeks premature, how long after birth would you conduct a
52 week assessment, after correcting for prematurity?
How do socioeconomic status (maternal education) and prematurity to
influence developmental outcome?
What is the impact of variables such as maternal sensitivity on outcome – on
which infants do they have the greatest impact?
What interventions might improve the outcomes of premature infants
(Kangaroo care, other types of physical contact) – please describe.
How do you think public health policy should be structured to prevent
negative developmental outcomes?
What are the Fetal Origins of Adult Disease?
Infant mortality rate (Ascending)
The rate in the United
States is 5.98, and there
are 48 countries with
lower rates, although
many of those use a less
stringent definition of
mortality than the US
http://en.wikipedia.org/wiki/List_of_countries_by_infant_mortality_rate
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Is mortality rate decreasing?
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Predicting prematurity
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Definition: 37 weeks gestational age or less
Associated with low birthweight, > 2,500 g
Incidence is linked to social risk and ethnicity
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socioeconomic status
Ethnicity
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Norway
Caucasian American
African American
3 per 1,000
5.5 per 1,000
13.5 per 1,000
Premature infants differ
in degree of prematurity,
in related medical problems,
and social risks
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More premature - reduced survival
(survival rates increase over historical time)
Weeks Gestation
Survival
21 weeks
0%
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22 weeks
0-10%*
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23 weeks
10-35%
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24 weeks
40-70%
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25 weeks
50-80%
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26 weeks
80-90%
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27 weeks
>90%
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30 weeks
>95%
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34 weeks
>98%
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A baby's chances for
survival increases 3-4%
per day between 23 and
24 weeks of gestation and
about 2-3% per day
between 24 and 26 weeks
of gestation. After 26
weeks the rate of survival
increases at a much slower
rate because survival is
high already.
http://www2.medsch.wisc.edu/childrenshosp/parents_of_preemies/toc.html
Survival
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The most important predictors
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greater gestational age
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heavier birth weight
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absence of severe breathing problems,
congenital abnormalities, and other diseases
like infections
At a given age/weight
Male infants are slightly less mature and
have a slightly higher risk of dying than
female infants.
 African-American babies have a slightly
better survival than Caucasian
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most other groups are intermediate between the
two
Significant disability
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Moderate or severe mental retardation,
inability to walk without assistance,
blindness or deafness
More extreme prematurity is associated
with greater risk of these conditions.
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At 23-24 weeks of gestation, risk is about 50%.
As gestational age increases, the risk of
significant disability declines dramatically.
More developmental problems as
birth weight decreases
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ELBW infants are more likely than higher birth weight infants to
demonstrate mild (<85) to significant (<70) delays on the Mental
Scales (MDI) and Psychomotor Scales (PDI) of the Bayley Scales
(BSID-II)
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66% and 57% of ELBW children scored below the normative range on the
MDI and PDI, respectively, at 18 to 22 months corrected age
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Poor performance on these measures may reflect early
deficits in behavior regulation among ELBW infants
including difficulty adapting to change, difficulty
sustaining attention, increased activity level, increased
need for examiner support and less persistence in
attempting to complete tasks
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Shankaran, 2004; 5 Vohr, B.R. 2000; 6 Vohr, B.R. 2005; 3 Walsh, M.C. 2005
Anderson, P. 2003; 27 Leonard, C.H. 2001; 9 Saigal, S. 2001; 19 Sajaniemi,
N. 2001; 26 Weiss, S.J. 2004; 10 Whitfield, M.F. 1997
ELBW infants at risk at 18 months
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25% had an abnormal neurologic exam;
37% had a Bayley II Mental MDI <70;
29% had a Psychomotor PDI <70,
9% had vision & 11% had hearing impairment
Increased morbidity: decreasing birth weight; lung disease;
IVH 3-4 (brain hemorrhage), necrotizing enterocolitis
Decreased morbidity: female gender, higher maternal
education, and white race.
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Vohr, B. R. et al., (2000). Neurodevelopmental and Functional
Outcomes of Extremely Low Birth Weight Infants in the National
Institute of Child Health and Human Development Neonatal
Research Network, 1993-1994. Pediatrics, 105(6), 1216-1226.
Big picture
Continuous advances in medical technology
mean that younger and lighter babies can be
saved
 Does this mean an increase in the
proportion of surviving infants who have
disabilities?
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Survival improving—illness constant?
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Survival in infants 501-1500 g improved,
 84%
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(1995-1996), 80% in 1991, 74% in 1988.
Increased survival not associated with
increased major morbidities 1991-1996
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CLD (chronic lung disease; 23%), proven NEC (7%),
and severe ICH (11%)—did not change
 Mortality & major morbidity remain high for
smallest: <600 g at birth.
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Lemons, J. A., Bauer, C. R., et al. & Network, N. N. R. (2001). Very Low Birth Weight Outcomes of
the National Institute of Child Health and Human Development Neonatal Research Network [14
participating centers], January 1995 Through December 1996. PEDIATRICS, 107(1), e1.
Behavior predicts cognitive/motor
development in ELBW children.
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18 month Behavior Record Scale (BRS)
30 month MDI and PDI
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Controlling for gender, birth weight, maternal
income, maternal education, 18-month MDI
and 18 month PDI,
in identical models, 18 month BRS Motor
Quality predicted both 30-month MDI and
30-month PDI.
Messinger, Lambert, Bauer et al., 2010
What’s corrected age?
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If baby born 10 weeks
early
52 weeks after birth
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comes 10 weeks early
Only 30 weeks gestation
Not 40 weeks
So its 82 – not 92 – weeks
of development after
conception
Solution: Correct (wait)
10 weeks
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Non-Premie
Gives premies a chance to
get on course
Correct until 2 or 3 years
40
52
Gestation
52 weeks after birth
Correction
Premie
30
0
20
52
40
60
10
80
100
Predictors of disability
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Identifiable brain abnormalities
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such as more severe intraventricular
hemorrhages (IVH)
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may occur before birth or in the nursery
Babies who have been the sickest and/or
remained sick for long periods of time
(several weeks).
APGAR (0 – 10)
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Each category summed
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Appearance (0-2)
Pulse (0-2)
Grimace (0-2)
Activity (0-2)
Respiration (0-2)
Add ‘em up
 3 or below means baby in danger
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so repeat APGAR every 5 minutes
Prematurity in context
Prematurity is a biological risk factor
 but outcome is also associated with social
risk factors
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The effects of biological and social
risk factors on special education
placement: Birth weight and
maternal education as an example
Hollomon, H.A. Dobbins, D. R., &
Skott, K.G. (1998). Research in
Developmental Disabilities, 19(3),
281-294.
Relative risk of special education by
mom education & baby birth weight
4.5
4
3.5
3
2.5
2
1.5
4.19
3.17
2.65
2.08
1.53
2.07
2.05
1.54
1
1
0.5
0
> 12 y mom ed
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12 y mom ed
< 12 y mom ed
NBW
LBW
VLBW
Agree or disagree?
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Low Maternal Education associated with almost
one fifth of the children in special education
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associated with the highest percentage of special
education placements.
approximately one third of the children were born to
mothers who had less than 12 years of education.
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22% of the sample had mothers with LME in the Metropolitan
Atlanta Developmental Disabilities Study (Satcher, 1995).
Less than 1% of children receiving special
education services can be attributed to being
VLBW because it is a low prevalence condition.
Public policy: Target Low Maternal Education
Policy:
What’s the biggest population risk?
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Theoretical Framework
-Ecological models (e.g. Bronfenbrenner model)
Social Interaction Quality
-Preterm infants showed limited amount and poorer quality of
Interactions with parents
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• Maternal factors
-Less interactive
Gestational age
Birth weight
-SES
Physiological regulation (HRV) -Feeding route
Infant factors
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Romero
4 Month Results
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Positive affect, Social, and Communicative Competence:
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Higher vagal regulation less positive affect & communication at 4
months
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Fewer SES risks more optimal interactions at 4 months.
More neonatal health risks showed more positive affect at 4 months.
Quality of Play, Interest, and Attention:
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but showed greater increases over time
exceed those infants with lower vagal regulation.
Infants born closer to term were higher on this subscale at 4 months.
More SES risks poorer quality of this subscale at 4 months.
Dysregulation and Irritability:
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Higher vagal regulation implied less dysregulation and irritability.
Romero
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Interventions for the premature
infant: Kangaroo Care (KC)
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‘Holding a diaper-clad infant in skin-to-skin
contact, prone and upright on the chest of
the parent.
Subsequent text from http://www.adhb.govt.nz/newborn/guidelines/developmental/KangarooCare.htm
Initiated after acute risk has passed
 Developing and developed world?
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http://www.youtube.com/watch?v=gQwdlMnkhbA&feature=related
http://www.youtube.com/watch?v=5yl-prEacIM&feature=related daddy
Wrap Instructions: Kangaroo Care with a Wrap
Administer Kangaroo Care to
medically stable infants
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Exclusion Criteria
 First 5 days for infants less than 30 weeks
gestation…
 Unstable on respiratory support (CPAP or
ventilation)
 After major procedures or treatment e.g
extubation
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Reported Benefits of Kangaroo
Care
Decreased variation in heart and respiratory
rates, improved oxygenation, less
bradycardia…
 Maintains skin and core temperatures
through conduction of heat from the parent.
 Promotes optimal growth and development.
 Beneficial for sleep-wake organisation.
 Increases mother’s milk production unlimited access to breast.
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Sample study
Reduction hypothermia (10/44 vs 21/45)
 higher oxygen saturations (95.7 vs 94.8)
 decrease in respiratory rates (36.2 vs 40.7)
 No differences in hyperthermia, sepsis,
apnea, onset of breastfeeding and hospital
stay in two groups.
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 Randomized
controlled trial was performed over one
year: kangaroo mother care (KMC) vs. conventional
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1: Indian J Pediatr. 2005 Jan;72(1):35-8. Feasibility of kangaroo mother
care in Mumbai.Kadam S, Binoy S, Kanbur W, Mondkar JA, Fernandez A.
Family involvement, massage
therapy
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“Massage therapy has been notably
effective in preventing prematurity,
enhancing growth of infants, increasing
attentiveness, decreasing depression and
aggression, alleviating motor problems,
reducing pain, and enhancing immune
function. “
Massage therapy research.Field, Tiffany; Diego, Miguel; Hernandez-Reif, Maria. Developmental Review. Vol 27(1),
Mar 2007, 75-89.
Sensitive parenting helps children
at highest medical risk
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Parenting (6 & 12 months) that was sensitive to children's
focus of interest and not highly controlling or restrictive
predicted
Greater increases & faster rates of cognitive-language &
social development @ 6, 12, 24, 40 mos.
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Relations stronger for high risk (HR; n = 73)
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Vs. full-term n=112 & medically low risk but low birth weight, n=114
Sensitive behaviors may provide support HR children need
to learn in spite of early attentional and organizational
problems.
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Confounds?
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Landry, S. H., Smith, K. E., Miller-Loncar, C. L., & Swank, P. R. (1997). Predicting cognitive-language and social growth curves
from early maternal behaviors in children at varying degrees of biological risk. Developmental Psychology, 33(6), 1040-1053.
Mom
maintaining vs.
restrictiveness
Landry et al., 1997
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For both LBW & NBW
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‘Mothers' maintaining children's interests
supported 2- & 3½-yr skills 4½-yr cognitive
and social independence
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Directiveness supported children's early cognitive and
responsiveness skills
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High levels of maintaining interests across these
ages support later independence,
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but by 3½ yrs, high levels of this behavior had a negative
influence on cognitive and social independence at 4½ yrs.
but directiveness needs to decrease in relation to
children's increasing competencies.’
Landry, S. H., Smith, K. E., Swank, P. R., & Miller-Loncar, C. L. (2000). Early maternal and child influences on
children's later independent cognitive and social functioning. Child Development, 71, 358-375.
Responsive Parenting: Establishing Early Foundations for Social,
Communication, and Independent Problem-Solving Skills
(Landry, Swift, & Swank, 2006)
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Responsive parenting:
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Contingent responding
Emotional-affective support
Support for infant foci of attention
Language input that supports developmental needs
Intervention: PALS (Playing and Learning Strategies) v. DAS
(Developmental Assessment Screening)
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263 infants, 10 home visits between 6-10 months of age
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Mothers reviewed weekly experience, visitor described purpose of visit,
discussed educational videotapes, videotaped mothers, mothers critiqued
own behavior, discussed responsive strategies
Infants were videotaped and assessed at each visit
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Nayfeld
Influence of responsive parenting on infant
behavior: Intervention
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Increases in mother’s responsive behaviorsincrease in infant
skills in first year
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Responsiveness in all aspects improved more in target mothers
Greater changes in infant behaviors (cooperation, use of words, affect, problem
solving) in PALS
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Both with mother and novel adult
Responsiveness mediates impact on infant development
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General responsiveness construct, with 4 distinct factors
Contingent responsiveness, verbal encouragement, and restrictiveness are
mediators
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Fully mediated relationship
intervention became non-significant
Nayfeld
Catch-up facilitated by more optimal
social environment
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Brain plasticity
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Median PPVT-R increased from 88 (36 months) to 99
at (96 months) in 296 VLBW infants (600 to 1250 g)
45% of children gained 10 points or more
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Increasing age, 2-parent household, higher levels of
maternal education all associated with higher scores
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children with early-onset IVH and subsequent CNS injury had
lowest initial scores & the scores declined over time (interaction).
Change in cognitive function over time in very low-birth-weight [VLBW] infants (Ment et al, 2003, JAMA, 289, 705-71
Long-term outcome: Educational
disadvantage but lower risk-taking
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Very-low-birth-weight infants as young adults
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Fewer VLBW adults graduate hi school: 74% vs 83%
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VLBW men, but not women, significantly less likely than controls
to be in postsecondary study (30% vs. 53%, P=0.002).
VLBW lower IQ (87 vs 92) & academic achievement
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242 VLBWs born ‘77-79 (at 1179 g) vs 233 normal birth weight
Higher rates of neurosensory impairments (10% vs. <1%) and
subnormal height (10% vs. 5%, P=0.04).
VLBW group reported less alcohol & drug use &
lower rates of pregnancy
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differences exist in those without neurosensory impairment.
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Hack, M., Flannery, D. J., Schluchter, M., Cartar, L., Borawski, E., & Klein, N. (2002). Outcomes in Young
Adulthood for VLBW Infants. New England Journal of Medicine, 346(3), 149-157.
Why?
The fetal origins of adult disease
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“David Barker pioneered the idea that the 20th century
epidemic of coronary heart disease in Western countries
might have originated in fetal life.1Paradoxically, the
epidemic coincided with improved standards of living and
nutrition, yet in Britain its greatest impact was in the most
deprived areas. Barker observed that early in the 20th
century these areas had the highest rates of neonatal
mortality and by inference the highest rates of low birth
weight. He postulated that impaired fetal growth might
have predisposed the survivors to heart disease in later
life.”
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BMJ 2001;322:375-376 ( 17 February )
Fetal Origins of Adult Disease:
Concepts and Controversies
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Association of low birthweight with
increased risk of coronary heart disease,
stroke, and type 2 diabetes.
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controlling for lifestyle factors such as smoking,
physical activity, occupation, income, dietary
habits, and childhood socioeconomic status.
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NeoReviews Vol.5 No.12 2004 e511
© 2004 American Academy of Pediatrics. Rebecca Simmons*
Infants are compensating for earlier weight
loss in a way that does not bode well longterm
Messinger
Mechanism of effects?
Combination of small size at birth and
during infancy, followed by accelerated
weight gain from age 3 to 11 years, predicts
large differences in CHD, type 2 diabetes
and hypertension.
 Mechanisms: developmental plasticity and
compensatory growth.
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Int J Epidemiol. 2002 Dec;31(6):1235-9. Links. Fetal origins of adult disease: strength of
effects and biological basis. Barker DJ, Eriksson JG, Forsén T, Osmond C.
Additional readings
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Messinger, D., Dolcourt, J., King, J., Bodnar, A., & Beck, D. (1996). The survival and developmental
outcome of extremely low birthweight infants. Infant Mental Health Journal, 17(4), 375-385.
Hollomon, H.A. Dobbins, D. R., & Skott, K.G. (1998). The effects of biological and social risk
factors on special education placement: Birth weight and maternal education as an example.
Research in Developmental Disabilities, 19(3), 281-294.
Infant Health and Development Project (1990). Enhancing the outcomes of low-birth-weight,
premature infants: A multisite, randomized trial. Journal of the American Medical Association,
263(22), 3035-3042.
Brooks-Gunn, J., McCarton, C., McCormick, M. C., & Klebanov, P. K. (1998). The contribution of
neighborhood and family income to developmental test scores over the first three years of life. Child
Development, 69(5), 1420-1436.
Vohr, B. R., Wright, L. L., Dusick, A. M., Mele, L., Verter, J., Steichen, J. J., Simon, N. P., Wilson,
D. C., Broyles, S., Bauer, C. R., Delaney-Black, V., Yolton, K. A., Fleisher, B. E., Papile, L.-A., &
Kaplan, M. D. (2000). Neurodevelopmental and Functional Outcomes of Extremely Low Birth
Weight Infants in the National Institute of Child Health and Human Development Neonatal Research
Network, 1993-1994. Pediatrics, 105(6), 1216-1226.
Susan Landry, Developmental Psychology.
Zeanah, C. on developmental risk. J am acad child and adol psychiatry '97 362.
Review Syllabus
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Syllabus