Gestational Age and Basic School Achievements: A National Follow-up Study in Denmark
ABSTRACT Children born at <32 weeks' gestation are at increased risk of intellectual impairment. Few studies have focused on the majority of preterm children born at 32 to 36 weeks' gestation. We aimed to investigate the association between the full range of gestational ages at birth and the risk of not completing basic school.
This longitudinal, register-based study included all live-born infants in Denmark from 1988 to 1989. Data were obtained from national registers. School achievements were evaluated by using the examination marks. The association between gestational age and not completing basic school was estimated, taking into account the effect of their parents' educational level, being small for gestational age, plurality, and cerebral palsy.
The cohort constituted 120,585 infants, of whom 118,281 (98.6%) were alive in 2007. Of these infants, 5.01% (n = 5.928) were born before 37 weeks' gestation. Of the subjects born before 37 weeks' gestation, 11.5% (95% confidence interval: 10.7-12.4) did not complete basic school compared with 7.5% (95% confidence interval: 7.3-7.6) of those born at term. The percentage of subjects who did not complete basic school increased with decreasing gestational age. The increase was steeper at <31 weeks (4.2% per week) than at 31 to 36 weeks' gestation (0.5% per week).
The risk of not completing basic school increased with decreasing gestational age. The risk was moderate at ≥31 weeks' gestation and increased steeply at <31 weeks' gestation. The increase at <31 weeks' gestation was only partly explained by cerebral palsy.
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ABSTRACT: To investigate the influence of a range of prenatal and postnatal factors on cognitive development in preterm and term-born adolescents. Woodcock-Johnson III Tests of Cognitive Abilities were used to assess general intellectual ability and 6 broad cognitive abilities in 145 young adolescents aged approximately 12.5 years and born 25-41 weeks gestational age (GA). To study potential links between neurophysiologic and cognitive outcomes, corticomotor excitability was measured using transcranial magnetic stimulation and surface electromyography. The influence of various prenatal and postnatal factors on cognitive development was investigated using relative importance regression modeling. Adolescents with greater GA tended to have better cognitive abilities (particularly general intellectual ability, working memory, and cognitive efficiency) and higher corticomotor excitability. Corticomotor excitability explained a higher proportion of the variance in cognitive outcome than GA. But the strongest predictors of cognitive outcome were combinations of prenatal and postnatal factors, particularly degree of social disadvantage at the time of birth, birthweight percentile, and height at assessment. In otherwise neurologically healthy adolescents, GA accounts for little interindividual variability in cognitive abilities. The association between corticomotor excitability and cognitive performance suggests that reduced connectivity, potentially associated with brain microstructural abnormalities, may contribute to cognitive deficits in preterm children. It remains to be determined if the effects of low GA on cognitive outcomes attenuate over childhood in favor of a concomitant increase in the relative importance of heritability, or alternatively, if cognitive development is more heavily influenced by the quality of the postnatal environment.The Journal of pediatrics 05/2014; 165(1). DOI:10.1016/j.jpeds.2014.03.030 · 3.74 Impact Factor
Archives of Disease in Childhood - Fetal and Neonatal Edition 08/2014; 99(6). DOI:10.1136/archdischild-2014-306557 · 3.86 Impact Factor
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ABSTRACT: Objective To investigate the effect of gestational age, particularly late preterm birth (34-36 weeks gestation) and early term birth (37-38 weeks gestation) on school performance at age 7 years. Design Population-based prospective UK Millennium Cohort Study, consisting of linked educational data on 6031 children. Methods School performance was investigated using the statutory Key Stage 1 (KS1) teacher assessments performed in the third school year in England. The primary outcome was not achieving the expected level (>= level 2) of general performance in all three key subjects (reading, writing and mathematics). Other outcomes investigated subject-specific performance and high academic performance (level 3). Results 18% of full-term children performed below the expected KS1 general level, and risk of poor performance increased with prematurity: compared to children born at full-term, there was a statistically significant increased risk of poor performance in those born very preterm (<32 weeks gestation, adjusted RR 1.78, 95% CI 1.24 to 2.54), moderately preterm (32-33 weeks gestation, adjusted RR 1.71, 95% CI 1.15 to 2.54) and late preterm (34-36 weeks gestation, adjusted RR 1.36, 95% CI 1.09 to 1.68). Early term children performed statistically significantly worse in 4 out of 5 individual subject domains than full-term children, but not in the primary outcome (adjusted RR 1.07, 95% CI 0.94 to 1.23). Conclusions Late preterm, and to a lesser extent, early term birth negatively impact on academic outcomes at 7 years as measured by KS1 assessments.Archives of Disease in Childhood - Fetal and Neonatal Edition 06/2014; 99(6). DOI:10.1136/archdischild-2014-306124 · 3.86 Impact Factor