Prematurity

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Class 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? 

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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

Definition: 37 weeks gestational age or less Associated with low birthweight, > 2,500 g Incidence is linked to social risk and ethnicity

– socioeconomic status– Ethnicity

Norway 3 per 1,000 Caucasian American 5.5 per 1,000 African American 13.5 per 1,000

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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%

22 weeks 0-10%*

23 weeks 10-35%

24 weeks 40-70%

25 weeks 50-80%

26 weeks 80-90%

27 weeks >90%

30 weeks >95%

34 weeks >98%

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

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Survival

The most important predictors greater gestational age heavier birth weight absence of severe breathing problems,

congenital abnormalities, and other diseases like infections

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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– most other groups are intermediate between the

two

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Significant disability

Moderate or severe mental retardation, inability to walk without assistance, blindness or deafness

More extreme prematurity is associated with greater risk of these conditions. At 23-24 weeks of gestation, risk is about 50%.

As gestational age increases, the risk of significant disability declines dramatically.

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More developmental problems as birth weight decreases 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)

– 66% and 57% of ELBW children scored below the normative range on the MDI and PDI, respectively, at 18 to 22 months corrected age

Shankaran, 2004; 5 Vohr, B.R. 2000; 6 Vohr, B.R. 2005; 3 Walsh, M.C. 2005 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

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

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ELBW infants at risk at 18 months

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.

• 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.

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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?

Survival in infants 501-1500 g improved, 84% (1995-1996), 80% in 1991, 74% in 1988.

Increased survival not associated with increased major morbidities 1991-1996– 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. • 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.

Messinger, Lambert, Bauer et al., 2010

Behavior predicts cognitive/motor development in ELBW children.

18 month Behavior Record Scale (BRS) 30 month MDI and PDI– 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.

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What’s corrected age?

If baby born 10 weeks early 52 weeks after birth

– 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

– Gives premies a chance to get on course

– Correct until 2 or 3 years

30

40

52

52

10

0 20 40 60 80 100

Premie

Non-Premie

Gestation52 weeks after birthCorrection

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Predictors of disability

Identifiable brain abnormalities such as more severe intraventricular

hemorrhages (IVH) 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).

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APGAR (0 – 10) Each category summed

– 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

– so repeat APGAR every 5 minutes

Transfo

rmed

obste

trics

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Prematurity in context

Prematurity is a biological risk factor but outcome is also associated with social

risk factors

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.

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Relative risk of special education by mom education & baby birth weight

1

1.54

2.05

1.53

2.07

2.65

2.08

3.17

4.19

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

> 12 y mom ed 12 y mom ed < 12 y mom ed

NBWLBWVLBW

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Agree or disagree?

Low Maternal Education associated with almost one fifth of the children in special education– 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. 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

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Policy: What’s the biggest population risk?

Theoretical Framework

-Ecological models (e.g. Bronfenbrenner model)

Social Interaction Quality-Preterm infants showed limited amount and poorer quality of

Interactions with parents

Infant factors– Gestational age– Birth weight– Physiological regulation (HRV)

Romero

• Maternal factors-Less interactive

-SES

-Feeding route

4 Month Results Positive affect, Social, and Communicative Competence:

– Higher vagal regulation less positive affect & communication at 4 months

but showed greater increases over time exceed those infants with lower vagal regulation.

– 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:– 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:– Higher vagal regulation implied less dysregulation and irritability.

Romero

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Interventions for the premature infant: Kangaroo Care (KC)

‘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? 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

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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

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.

Randomized controlled trial was performed over one year: kangaroo mother care (KMC) vs. conventional

• 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.

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Family involvement, massage therapy

“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.

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Sensitive parenting helps children at highest medical risk 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.

– Relations stronger for high risk (HR; n = 73)– 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.

– Confounds? – 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.

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Mom maintaining vs. restrictivenessLandry et al., 1997

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For both LBW & NBW

‘Mothers' maintaining children's interests supported 2- & 3½-yr skills 4½-yr cognitive and social independence

– Directiveness supported children's early cognitive and responsiveness skills

but by 3½ yrs, high levels of this behavior had a negative influence on cognitive and social independence at 4½ yrs.

High levels of maintaining interests across these ages support later independence,

– 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)

Responsive parenting: – 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)

– 263 infants, 10 home visits between 6-10 months of age– 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

Nayfeld

Influence of responsive parenting on infant behavior: Intervention

Increases in mother’s responsive behaviorsincrease in infant skills in first year

– Responsiveness in all aspects improved more in target mothers– Greater changes in infant behaviors (cooperation, use of words, affect, problem

solving) in PALS Both with mother and novel adult

Responsiveness mediates impact on infant development– General responsiveness construct, with 4 distinct factors– Contingent responsiveness, verbal encouragement, and restrictiveness are

mediators Fully mediated relationship intervention became non-significant

Nayfeld

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Catch-up facilitated by more optimal social environment Brain plasticity

– 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– Increasing age, 2-parent household, higher levels of

maternal education all associated with higher scores • 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

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Long-term outcome: Educational disadvantage but lower risk-taking

Very-low-birth-weight infants as young adults 242 VLBWs born ‘77-79 (at 1179 g) vs 233 normal birth weight

Fewer VLBW adults graduate hi school: 74% vs 83% 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

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– differences exist in those without neurosensory impairment.

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

“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.”

– BMJ 2001;322:375-376 ( 17 February )

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Fetal Origins of Adult Disease:Concepts and Controversies

Association of low birthweight with increased risk of coronary heart disease, stroke, and type 2 diabetes.

– controlling for lifestyle factors such as smoking, physical activity, occupation, income, dietary habits, and childhood socioeconomic status.

• 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 long-term

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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.

– 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.

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Additional readings

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.

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Review Syllabus

Syllabus