Journal of Pediatric Psychology, Vol. 25, No. 5, 2000, pp. 353-358
© 2000 Society of Pediatric Psychology
Brief Report : Birth Status, Medical Complications, and Social Environment : Individual Differences in Development of Preterm, Very Low Birth Weight Infants
1 University of Notre Dame, 2 Memorial Hospital of South Bend, Indiana
All correspondence should be sent to Penny J. Miceli, Department of Psychology, University of Notre Dame, Notre Dame, Indiana 46556. E-mail : miceli. 3{at}nd.edu Cynthia Miller-Loncar is currently at the Infant Development Center, Women and Infants' Hospital, Providence, Rhode Island
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Abstract |
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Objective : To assess whether medical complications mediate the relationship between birth status (i.e., birth weight and gestational age) and developmental outcome of preterm, very low birth weight (VLBW) infants, as well as the role of the early social environment (maternal distress and social support) in infant development.
Method : Birth status and medical complication information was collected during the child's NICU stay. Maternal distress was assessed with the Beck Depression Inventory and the Parenting Stress Index at 4 months corrected infant age. Social support was measured with the Dunst Scales at 4 months corrected age. Child development measures were collected at 4 and 13 months corrected age (Bayley MDI and PDI), and at 36 months chronological age (PPVT-R and Achenbach CBCL).
Results : Medical complications mediated the birth status-outcome relationship at 4 and 13 months, but not at 36 months. The 36-month outcomes were predicted by 4-month maternal distress and social support.
Conclusions : Prematurity and VLBW are indirectly related to early developmental outcome through their association with medical complications. However, by 36 months, developmental outcomes are more closely related to aspects of the early social environment than to early physiological factors.
Key words: preterm infants; very low birth weight; medical complications; cognitive development; behavioral development; stress; depression; social support.
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Introduction |
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Clinicians and researchers alike have noted the wide variability in developmental outcome of preterm, low birth weight (LBW) infants. An increasingly common assumption is that medical complications, rather than degree of prematurity/LBW per se, drive developmental outcomes (Creasey, Jarvis, Myers, Markowitz, & Kerkering, 1993
; Myers,
1992). However, the validity of this assumption has not been
adequately tested in the literature and awaits explicit support with
statistical mediation models.
In addition, researchers have increasingly emphasized the role of the
social context on development after the child leaves the hospital environment
(Beckwith & Parmelee, 1986
; Beckwith & Rodning, 1996
; Sigman, Cohen, Beckwith, & Parmelee,
1981). Giving birth prematurely can introduce a considerable
amount of stress into the lives of the caregivers
(Lowenthal, 1987), which may
significantly impair the parents' ability to provide an environment conducive
to resiliency. To buffer the distress parents of high-risk infants may
experience, adequate social support networks may be needed
(Crnic, Greenberg, Ragozin, Robinson,
& Basham, 1983).
In this study, we evaluated the importance of infant birth status, medical complications, and the social environment for developmental outcome in a sample of preterm, VLBW infants across the first 3 years of life. We hypothesized that (1) although poor infant birth status would be associated with more negative developmental outcomes, this relationship would be mediated by the severity of the child's medical condition ; and (2) early environments characterized by greater maternal distress and less social support would be associated with more adverse outcomes across development.
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Method |
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Participants
Participants in the study included 30 infants and their mothers enrolled in a longitudinal study of preterm infant development conducted at a Level III neonatal intensive care unit (NICU). The participants were mostly Caucasian (93%), and mothers had a mean age of 27 years (range = 19-36). At the time of delivery, 61% of the mothers reported being married. Twenty-one percent of the mothers had not completed high school, 43% had a high school education, and 36% reported at least some postsecondary education (trade school, college, and/or postgraduate). The study initially included 60 participants, but due to attrition and/or missing data, the sample consists of 30 mother-infant pairs, with the exception of analyses regarding linguistic development, for which only 24 participants had data. The participants included here did not differ from those not included on birth status, medical complications, or demographic variables, with the exception that mothers not included in the report were slightly younger (mean age = 23 years, range = 15-36). Infants included in this report had an average birth weight of 1,000 grams (range = 490-1,510 grams), and an average gestational age of 27.9 weeks (range = 23.5-32 weeks).
Measures
To preserve power in the multiple regression analyses, we used several
composite variables as predictors. In cases where a composite was formed,
variables were first standardized using a z-transformation and then
averaged. Correlations between the variables contained in any given composite
were all statistically significant at the.05 level or better and are reported
where appropriate.
Infant Birth Status.
Each infant's birth status (recorded during the NICU stay) was represented
by a composite formed from his or her birth weight and gestational age
(r =.93, p <.001). A lower score on this composite
indicates a younger, smaller infant.
Infant Medical Complications.
The medical complications composite included the following variables taken
from the infant's medical record at discharge : 5-minute Apgar
(Apgar, 1962) score (reverse
scored) ; number of days the child received ventilator support ; number of
days the child received supplemental oxygen (separate from ventilator support)
; the number of days the infant received intravenous feedings, and the number
of days the child received gavage feedings. The correlations among these
variables ranged from.37 to.92 (average correlation =.66), and were all
statistically significant. A lower score on this composite indicates an infant
who experienced fewer medical complications during hospitalization.
Maternal Distress.
Maternal stress at 4 months corrected infant age was measured by
self-report using the Parenting Stress Index-Short Form (PSI-SF ;
Abidin, 1990). Test-retest
reliability for the PSI-SF is.84 (Abidin,
1990). Mother-reported depression was measured at this same time
using the Beck Depression Inventory (BDI ;
Beck & Steer, 1993).
Internal consistency for the Beck ranges from.73 to.92, and test-retest
reliability has been found to range from.48 to.86
(Beck, Steer, & Garbin,
1988). These measures were significantly correlated (r
=.81, p <.001) and were used to form a maternal distress composite
for each mother. A higher score on this composite indicates higher maternal
distress.
Maternal Social Support.
Mothers filled out the "frequency of contact" and
"support satisfaction" scales of the Dunst Social Support Scales
(Dunst, Trivette, & Deal,
1988) when their infant was 4 months corrected age. A composite
"informal" and "formal" support score was formed by
combining the appropriate items from each scale. First, each mother was given
a composite formal support score by averaging her standardized (z-transformed)
score for "frequency of contact" and "satisfaction"
with formal support sources. Second, each mother was similarly given a
composite informal support score by averaging her standardized (z-transformed)
score for "frequency of contact" and "satisfaction"
with informal support sources. Formal and informal support scales were
significantly correlated (r =.89, p <.001) and were
z-transformed and then averaged to create a global social support composite. A
higher score on this global social support composite indicates the mother's
perception of more adequate social support. Internal consistency for the
formal, informal, and global social support composites was adequate, with
coefficient alpha greater than.7 in each case.
Infant Developmental Outcome.
Infants were ministered the mental and motor scales of the Bayley Scales of
Infant Development (Bayley,
1969) at 4 and 13 months corrected infant age (with scores being
calculated relative to this adjusted age). Correlations between this version
of the Bayley and the newer Bayley II are reported to be.62 (MDI) and.63 (PDI)
(Bayley, 1994). At 36 months
chronological age, child linguistic development was assessed using the Peabody
Picture Vocabulary Test-R, form L (PPVT-R ; 1981). Split-half reliability for
the scale ranges from.67 to.88 for children 2-18 years
(Dunn & Dunn, 1981).
Correlation of standard scores on the PPVT-R and the newer PPVT-III are
reported to range from.83 to.89 (Williams
& Wang, 1997). In addition, a correlation of.68 has been
reported between the PPVT-R and the WISC-R
(Sattler, 1990). Maternal
report of child behavioral development was collected at 36 months using the
Achenbach Child Behavior Check List (CBCL ;
Achenbach & Edelbrock,
1986), which yields two broad-bank factors : internalizing and
externalizing behaviors. Reliability and validity of the CBCL are well
established (Achenbach,
1992).
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Results |
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Interrelationships of Infant Birth Status, Medical Complications, and Developmental Outcomes
We assessed the question of whether medical complications mediated birth status-outcome relations using Baron and Kenny's (1986
) approach. For
illustration purposes, here we describe in detail the results of this
procedure for the 4-month mental development outcome. As expected, birth
status and medical complications were significantly related, such that
younger, smaller infants experienced more medical complications (ß =
-.76, p <.001). When alone in the model, better initial birth
status (i.e., older gestational ages and heavier birth weights) was associated
with higher Bayley Mental Development Index scores (ß =.43, p
<.05), and this model explained 16% of the variance in mental development
scores. When both medical complications and birth status were entered into the
model, however, the relationship between birth status and Bayley MDI was
nonsignificant (ß = -.13, p >.05), indicating that medical
complications mediated the relationship between birth status and mental
development. With medical complications added to the model, 37% of the
variance in mental development scores was explained. These results, along with
those of similar models predicting 4-month motor and 13-month mental and motor
development, are summarized in Table
I. As shown, the same pattern of results emerged for all 4- and
13-month outcomes. In contrast, there was no relationship between infant birth
status or medical complications and 36-month outcomes.
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Relationship of Early Social Environment and Developmental
Outcome
Neither maternal distress nor social support was related to child
performance on the Bayley at 4 or 13 months. At 36 months, maternal distress
was related to child behavioral outcome such that children of mothers
reporting greater distress (stress and depression) at 4 months were rated as
showing more internalizing (r =.42, p <.05) and
externalizing (r =.63, p <.01) behaviors at 36 months.
Maternal distress was not related, however, to child linguistic functioning as
measured by the PPVT-R. In contrast, maternal social support was significantly
related to linguistic functioning, such that children of mothers reporting
greater support showed better receptive language functioning at 36 months
(r =.46, p <.05). In addition, maternal social support
was related to child internalizing behaviors ; thus, children of mothers
reporting greater support were rated as showing fewer internalizing behavior
problems at 36 months (r = -.42, p <.05). Maternal social
support at 4 months was not related to child externalizing behaviors.
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Discussion |
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As expected, the birth status of younger, smaller infants was associated with less optimal developmental outcomes at 4 and 13 months corrected age on the Bayley mental and psychomotor scales. However, results showed that the effect of infant birth status on developmental outcome is indirect, mediated by the medical condition of the child. The amount of variance accounted for with medical complications in the model was substantial, ranging from 22% to 37%, and in all cases an improvement over models with only infant birth status. These data suggest that prematurity or low birth weight per se does not place this population at risk ; rather, the medical complications that infants experience in the weeks and months following birth heighten risk. However, neither birth status nor medical complications were related to developmental measures taken at 36 months, suggesting that the role of such factors lessens with time.
In contrast, the importance of the early social environment became more evident over time in this study. Maternal distress (stress and depression) and social support, although unrelated to infant functioning at 4 and 13 months, were related to 36-month outcomes. Mothers reporting greater distress in response to the preterm birth at 4 months had children who displayed more behavioral difficulties, both of the internalizing and externalizing variety, at 3 years of age. Moreover, children of mothers reporting greater support at 4 months also demonstrated lower levels of internalizing behavior problems, as well as more advanced receptive language skills at 3 years, than children of mothers with less support.
Overall, the pattern of results shown in this study suggests that whereas
biological factors are a dominant influence on early outcomes of preterm
infants, the importance of the early social environment becomes evident in
later development. This latter finding is consistent with the work of
Weisglas-Kuperus, Baerts, Smrkovsky, and Sauer
(1993), who found that
relatively static social factors such as socioeconomic status, family
composition, and ethnic background became significant predictors of cognitive
scores after 2 years of age, but not before. This study is different in that
it examined more psychologically oriented characteristics of the environment
(e.g., maternal distress and social support), which varied considerably for
the mothers of this sample. Some mothers reported stress levels within the
clinical range, and depression scores at the upper end of the moderate
range.
There are several limitations of this study. First, because maternal
distress and child behavioral ratings were both evaluated by the mother, the
relationship may be due to shared method variance. Relatedly, we acknowledge
that the relationship between maternal distress and child behavior may be
genetically driven, rather than environmentally. Second, the relatively small
sample size may have resulted in low power for some analyses. With the current
sample (n = 30), the estimated power for detecting moderate
correlations (in the.4 range) was 80%
(Cohen & Cohen, 1983).
Thus, other more subtle relationships between the constructs of interest may
have gone undetected due to sample size limitations. Third, the higher
attrition rate for younger mothers of the sample may have resulted in
underestimation of the importance of some constructs, particularly maternal
distress and social support, which may have a more pronounced impact for those
mothers.
This study has important clinical implications. Specifically, these results suggest that efforts to enhance the development of preterm infants must take into consideration the multiple influences operating in the lives of these children and their families, in addition to attending to the child's early medical needs. An understanding of the timing of importance of physical versus social factors may help parents form appropriate expectations regarding the future course of their child's development. Although biological factors may inhibit the preterm child's development early in life, the role of such factors will likely diminish over time. In addition, intervention efforts targeting the potentially malleable psychological responses of the mother to the preterm birth, as well as her support network, may be particularly valuable for enhancing child development.
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Acknowledgments |
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This research was supported by a training grant from the National Institutes of Health (HD-40123), and a research grant from the Center for the Study of Children, Notre Dame, Indiana 46556. We thank the families participating in this study, the New-born Intensive Care Unit Staff of Memorial Hospital of South Bend, Deirdre Mylod, and Mary O'Callaghan. Portions of this research were presented at the meeting of the Society for Research in Child Development, Washington, D.C., in April 1997.
Received April 21, 1998; revision received October 2, 1998; revision received February 24, 1999; accepted April 13, 1999
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References |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionReferences |
|---|
Abidin, R. (1990). Parenting Stress Index/Short Form. Charlottesville, VA : Pediatric Psychology Press.
Achenbach, T. M. (1992). Manual for the Child Behavior Checklist/2-3 and 1992 Profile. Burlington : University of Vermont, Department of Psychiatry.
Achenbach, T. M., & Edelbrock, E. S. (1986). Child Behavior Checklist and Youth Self-Report. Burlington, VT : Author.
Apgar, V. (1962). The newborn (Apgar) scoring system. Pediatric Clinics of North America, 13, 645.
Baron, R. M., & Kenny, D. A. (1986). The moderatormediator variable distinction in social psychological research : Conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology, 51, 345-353.
Bayley Scales of Infant Development. (1969/1994). Manual for the Bayley Scales of Infant Development. New York : Psychological Corp.
Beck, A. T., & Steer, R. A. (1993). Beck Depression Inventory Manual. San Antonio : Psychological Corp.
Beck, A. T., Steer, R. A., & Garbin, M. (1988). Psychometric properties of the Beck Depression Inventory : Twentyfive years of evaluation. Clinical Psychological Review, 8, 77-100.
Beckwith, L., & Parmalee, A. H. (1986). EEG patterns of preterm infants, home environment, and later IQ. Child Development, 57, 777-789.[Web of Science][Medline]
Beckwith, L., & Rodning, C. (1996). Dyadic processes between mothers and preterm infants : Development at ages 2 to 5 years. Infant Mental Health Journal, 17, 322-333.
Cohen, J., & Cohen, P. (1983). Applied multiple regression/correlation analysis for the behavioral sciences. Hillsdale, NJ : Erlbaum.
Creasey, G. L., Jarvis, P. A., Myers, B. J., Markowitz, P. I., & Kerkering, K. W. (1993). Mental and motor development for three groups of premature infants. Infant Behavior and Development, 16, 365-372.
Crnic, K. A., Greenberg, M. T., Ragozin, A. S., Robinson, N. M., & Basham, R. B. (1983). Effects of stress and social support on mothers and premature and full-term infants. Child Development, 54, 209-217.[Web of Science][Medline]
Dunn, L. M., & Dunn, L. M. (1981). Peabody Picture Vocabulary Test-Revised. Circle Pines, MN : American Guidance Services.
Dunst, C., Trivett, C., & Deal, A. (1988). Enabling and empowering families. Cambridge, MA : Brookline Books.
Lowenthal, B. (1987). Stress factors and their alleviation in parents of high risk pre-term infants. Exceptional Child, 34, 21-30.
Myers, B. J., Jarvis, P. A., Creasy, G. L., Kerkering, K. W., Markowitz, P. I., & Best, A. L. (1992). Prematurity and respiratory illness : Brazelton Scale (NBAS) performance of preterm infants with bronchopulmonary dysplasia (BPD), Respiratory Distress Syndrome (RDS), or no respiratory illness. Infant Behavior and Development, 15, 27-41.
Sattler, J. M. (1990). Assessment of children. 3rd ed. San Diego : Jerome M. Sattler.
Sigman, M., Cohen, S. E., Beckwith, L., & Parmelee, A. H.
(1981). Social and familial influences on the development of
preterm infants. Journal of Pediatric Psychology,
6, 1-13.
Weisglas-Kuperus, N., Baerts, W., Smrkovsky, M., & Sauer, P. J.
(1993). Effects of biological and social factors on the cognitive
development of very low birth weight children.
Pediatrics, 92,
658-665.
Williams, K. T., & Wang, J. (1997). Technical references to the Peabody Picture Vocabulary Test (3rd. ed.). Circle Pines, MN : American Guidance Service.
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