Nancy Klein

BACKGROUND: Very-low-birth-weight infants (those weighing less than 1500 g) born during the initial years of neonatal intensive care have now reached young adulthood. METHODS: We compared a cohort of 242 survivors among very-low-birth-weight infants born between 1977 and 1979 (mean birth weight, 1179 g; mean gestational age at birth, 29.7 weeks) with 233 controls from the same population in Cleveland who had normal birth weights. We assessed the level of education, cognitive and academic achievement, and rates of chronic illness and risk-taking behavior at 20 years of age. Outcomes were adjusted for sex and sociodemographic status. RESULTS: Fewer very-low-birth-weight young adults than normal-birth-weight young adults had graduated from high school (74 percent vs. 83 percent, P=0.04). Very-low-birth-weight men, but not women, were significantly less likely than normal-birth-weight controls to be enrolled in postsecondary study (30 percent vs. 53 percent, P=0.002). Very-low-birth-weight participants had a lower mean IQ (87 vs. 92) and lower academic achievement scores (P<0.001 for both comparisons). They had higher rates of neurosensory impairments (10 percent vs. <1 percent, P<0.001) and subnormal height (10 percent vs. 5 percent, P=0.04). The very-low-birth-weight group reported less alcohol and drug use and had lower rates of pregnancy than normal-birth-weight controls; these differences persisted when comparisons were restricted to the participants without neurosensory impairment. CONCLUSIONS: Educational disadvantage associated with very low birth weight persists into early adulthood.

BACKGROUND: Since the mid-1980s, increasing numbers of children with birth weights under 750 g have survived to school age. METHODS: We matched a regional cohort of 68 surviving children born from 1982 through 1986 with birth weights under 750 g (mean, 670 g; gestational age, 25.7 weeks) with 65 children weighting 750 to 1499 g at birth and 61 children born at term. Growth, neurosensory status, and functioning at school age in the three groups were compared. Associations of biologic and social risk factors with major developmental outcomes were examined by means of logistic-regression analyses. RESULTS: Children with birth weights under 750 g were inferior to both comparison groups in cognitive ability, psychomotor skills, and academic achievement. They had poorer social skills and adaptive behavior and more behavioral and attention problems. The mean (+/- SD) Mental Processing Composite score for the cohort was 87 +/- 15, as compared with 93 +/- 14 for children with birth weights of 750 to 1499 g and 100 +/- 13 for children born at term (P < 0.001). The rates of mental retardation (IQ < 70) in the three groups were 21, 8, and 2 percent, respectively; the rates of cerebral palsy were 9, 6, and 0 percent; and the rates of severe visual disability were 25, 5, and 2 percent. Major cerebral ultrasonographic abnormalities were associated with mental retardation (odds ratio, 5.4; 95 percent confidence interval, 1.8 to 15.8) and cerebral palsy (odds ratio, 15.2; 95 percent confidence interval, 3.0 to 77.4). Oxygen dependence at 36 weeks was associated with mental retardation (odds ratio, 4.5; 95 percent confidence interval, 1.2 to 10.7) and severe visual disability (odds ratio, 4.3; 95 percent confidence interval, 1.3 to 14.2). Social disadvantage, though associated with several neuropsychological outcomes, was not associated with major developmental impairment. CONCLUSIONS: Children with birth weights under 750 g who survive represent a subgroup of very-low-birth-weight children who are at high risk for neurobehavioral dysfunction and poor school performance.

OBJECTIVE: The Bayley Scales of Infant Development, Second Edition (BSID II) are commonly used to assess outcomes of extremely low birth weight (ELBW) infants. We sought to assess the predictive validity of the BSID II Mental Developmental Index (MDI) for cognitive function at school age. DESIGN/METHODS: Of 330 ELBW infants admitted in 1992-1995, 238 (72%) survived to the age of 8 years, of whom 200 (84%) were tested at both 20 months' corrected age (CA) and 8 years. Mean birth weight was 811 g, mean gestational age was 26.4 weeks, 41% were boys, and 60% were black. Measures included the BSID II at 20 months' CA and the Kaufman Assessment Battery for Children (KABC) Mental Processing Composite (MPC) at 8 years' postnatal age. BSID II MDI and MPC scores were compared and the predictive validity calculated for all 200 ELBW children and for the 154 ELBW neurosensory-intact subgroup. Predictors of stability or change in cognitive scores were examined via logistic regression adjusting for gender and sociodemographic status. RESULTS: For all ELBW children, the mean MDI was 75.6 +/- 16 versus a mean KABC of 87.8 +/- 19. For the neurosensory-intact subgroup, the mean MDI was 79.3 +/- 16 and the mean KABC was 92.3 +/- 15. Rates of cognitive impairment, defined as an MDI or KABC of <70, dropped from 39% at 20 months' CA to 16% at 8 years for the total ELBW population and from 29% to 7% for the neurosensory-intact subgroup. The positive predictive value of having an MPC of <70 given an MDI of <70 was 0.37 (95% confidence interval [CI]: 0.27, 0.49) for all ELBW infants, 0.20 (95% CI: 0.10, 0.35) for the neurosensory-intact subgroup, and 0.61 (95% CI: 0.42, 0.77) for the neurosensory-impaired subgroup. The negative predictive values were 0.98, 0.99, and 0.85 for the 3 groups, respectively. Neurosensory impairment at 20 months' CA predicted lack of improvement of cognitive function (odds ratio: 6.9; 95% CI: 2.4, 20.2). Children whose cognitive scores improved between 20 months and 8 years had significantly better school performance than those whose scores stayed at <70, but they did less well than those whose scores were persistently >70. CONCLUSIONS: The predictive validity of a subnormal MDI for cognitive function at school age is poor but better for ELBW children who have neurosensory impairments. We are concerned that decisions to provide intensive care for ELBW infants in the delivery room might be biased by reported high rates of cognitive impairments based on the use and presumptive validity of the BSID II MDI.

BACKGROUND: We tested the hypothesis that very-low-birth-weight (less than 1.5 kg) infants with perinatal growth failure whose head size is not normal by eight months of age (corrected for prematurity) have significantly poorer growth and neurocognitive abilities at school age than very-low-birth-weight children with a normal head size at eight months. We also hypothesized that these differences would persist even after control for major neurologic impairment and perinatal and sociodemographic risk factors. METHODS: We have followed a cohort of very-low-birth-weight children since their birth during the period 1977 to 1979. At eight to nine years of age 249 children were evaluated with a neurologic examination and tests of intelligence; receptive and expressive language skills; speech, reading, mathematics, and spelling aptitude; visual and fine motor abilities; and behavior. Ages were corrected for premature birth. RESULTS: Among these 249 very-low-birth-weight children, head size was subnormal (less than the mean -2 SD for age) at birth in 30 (12 percent), at term in 57 (23 percent), and at eight months in 33 (13 percent). As compared with the 216 children with normal head sizes, the 33 children with subnormal head sizes at the age of eight months had significantly lower mean birth weights (1.1 vs. 1.2 kg) and higher neonatal risk scores (71 vs. 53) and at the age of eight years had a higher incidence of neurologic impairment (21 percent vs. 8 percent) and lower IQ scores (mean verbal, 84 vs. 98). Even among the children without neurologic abnormalities, a subnormal head size at eight months of age was predictive of poorer verbal and performance IQ scores at eight years of age; lower scores for receptive language, speech, reading, mathematics, and spelling; and a higher incidence of hyperactivity. In multiple regression analyses to control for socioeconomic and neonatal risk factors, intrauterine growth failure, birth weight, and neurologic impairment, a subnormal head size at eight months of age had an independently adverse effect on IQ and on scores for receptive language, speech, reading, and spelling. CONCLUSIONS: In very-low-birth-weight infants, perinatal growth failure, as evidenced by a subnormal head circumference at eight months of age, is associated with poor cognitive function, academic achievement, and behavior at eight years of age.

CONTEXT: Information on the school-age functioning and special health care needs of extremely low-birth-weight (ELBW, <1000 g) children is necessary to plan for medical and educational services. OBJECTIVE: To examine neurosensory, developmental, and medical conditions together with the associated functional limitations and special health care needs of ELBW children compared with normal-birth-weight (NBW) term-born children (controls). DESIGN, SETTING, AND PARTICIPANTS: A follow-up study at age 8 years of a cohort of 219 ELBW children born 1992 to 1995 (92% of survivors) and 176 NBW controls of similar sociodemographic status conducted in Cleveland, Ohio. MAIN OUTCOME MEASURES: Parent Questionnaire for Identifying Children with Chronic Conditions of 12 months or more and categorization of specific medical diagnoses and developmental disabilities based on examination of the children. RESULTS: In logistic regression analyses adjusting for sociodemographic status and sex, ELBW children had significantly more chronic conditions than NBW controls, including functional limitations (64% vs 20%, respectively; odds ratio [OR], 8.1; 95% confidence interval [CI], 5.0-13.1; P<.001), compensatory dependency needs (48% vs 23%, respectively; OR, 3.0; 95% CI, 1.9-4.7; P<.001), and services above those routinely required by children (65% vs 27%, respectively; OR, 5.4; 95% CI, 3.4-8.5; P<.001). These differences remained significant when the 36 ELBW children with neurosensory impairments were excluded. Specific diagnoses and disabilities for ELBW vs NBW children included cerebral palsy (14% vs 0%, respectively; P<.001), asthma (21% vs 9%; OR, 3.0; 95% CI, 1.6-5.6; P = .001), vision of less than 20/200 (10% vs 3%; OR, 3.1; 95% CI, 1.2-7.8; P = .02), low IQ of less than 85 (38% vs 14%; OR, 4.5; 95% CI, 2.7-7.7; P<.001), limited academic skills (37% vs 15%; OR, 4.2; 95% CI, 2.5-7.3; P<.001), poor motor skills (47% vs 10%; OR, 7.8; 95% CI, 4.5-13.6; P<.001), and poor adaptive functioning (69% vs 34%; OR, 6.5; 95% CI, 4.0-10.6; P<.001). CONCLUSION: The ELBW survivors in school at age 8 years who were born in the 1990s have considerable long-term health and educational needs.