Most preemies will grow up without any major difficulties but the tiniest prems are at an increased risk for developmental delay and intellectual impairment.

General intelligence is usually estimated by performance on a number of different types of tests, including memory, attention, visual perception, visual motor skills, visual spatial processing, abstract reasoning, and language processes. You will sometimes here medical professionals refer to these skills as cognitive processes.

The majority of preterm children have normal IQ scores however preemies are at greater risk for impaired intellectual function. Babies born earlier and smaller are at greater risk than those born closer to term

(Wechsler, 1981)(Aylward, 2005; Bhutta, et al., 2002; H. G. Taylor, Klein, & Hack, 2000)

What do IQ scores mean?

IQ stands for intelligence quotient. Sometimes medical professionals will refer to an IQ score to represent how an individual is generally performing relative to the "normal" or "average" person of the same age. The table below provides definitions for ranges of scores.

Preemies & IQ scores

• 65% of preterm children have an IQ within the normal range or higher
• 25% of preterm children have an IQ within the borderline range
• 5 – 10% of preterm children have severe IQ impairment

Research examples in detail

A lot of research has been conducted to determine the intellectual outcomes of children who were born preterm in comparison to their peers who were born at term.

Preterm infants who are smaller and more immature at birth are at greater risk for severe intellectual impairment and borderline IQ scores. In a follow up study of ELBW (less than 1000 g) children at 8 years, the likelihood of an IQ less than 70 was 10 times greater than in the NBW group, and 3.4 times greater when those children with neurosensory impairments were excluded.

Infant and early childhood tests of intelligence and other “thinking” skills (i.e. memory, attention, learning etc.) do not necessarily mean that they will have poor IQ and academic functioning later in life. Conducting assessments of IQ (different types of thinking skills) at different ages in a preemies’ life is important to find out developmental change over time and preterm infants potential capacity to “catch-up” to their full term peers. One research group studied changes in cognitive performance over time in a low birth weight (less than 2000 g) group of preemies and found that the difference in IQ between low birth weight and normal birth weight children was smaller (4 IQ points) at age 11 years than at 5 years of age (7 IQ points).

Although an IQ score can provide information about a preterm child’s general thinking ability, it does not include information about specific or subtle difficulties or strengths in certain areas. Many preterm children have variable profiles, with strong performance in some areas but relative weaknesses in others, or general poor performance with relative strengths. Some have found that a general profile leans toward a relative strength in verbal-based tasks in comparison to non-verbal problem-solving skills (visual spatial).

(Botting, Powls, Cooke, & Marlow, 1998; R. W. Cooke, Foulder-Hughes, Newsham, & Clarke, 2004; Ito et al., 1996)(Siegel, 1981)

Technical Reference List

Aylward, G. P. (2005). Neurodevelopmental outcomes of infants born prematurely. J Dev Behav Pediatr, 26(6), 286-294.
Bhutta, A. T., Cleves, M. A., Casey, P. H., Cradock, M. M., & Anand, K. J. S. (2002). Cognitive and behavioral outcomes of school-aged children who were born preterm: a meta-analysis. Jama, 288(6).
Bax, M., Goldstein, M., Rosenbaum, P., Leviton, A., Paneth, N., Dan, B., et al. (2005). Proposed definition and classification of cerebral palsy, April 2005. Developmental Medicine and Child Neurology, 47(8), 571-576.
Botting, N., Powls, A., Cooke, R. W., & Marlow, N. (1998). Cognitive and educational outcome of very-low-birthweight children in early adolescence. Developmental Medicine and Child Neurology, 40(10), 652-660.
Cooke, R. W., Foulder-Hughes, L., Newsham, D., & Clarke, D. (2004). Ophthalmic impairment at 7 years of age in children born very preterm. Arch Dis Child Fetal Neonatal Ed, 89(3), 249-253.
Elgen, I., Sommerfelt, K., & Ellertsen, B. (2003). Cognitive performance in a low birth weight cohort at 5 and 11 years of age. Pediatr Neurol, 29(2), 111-116.
Elgen, I., Sommerfelt, K., & Ellertsen, B. (2003). Cognitive performance in a low birth weight cohort at 5 and 11 years of age. Pediatr Neurol, 29(2), 111-116.
Ito, J., Saijo, H., Araki, A., Tanaka, H., Tasaki, T., Cho, K., et al. (1996). Assessment of visuoperceptual disturbance in children with spastic diplegia using measurements of the lateral ventricles on cerebral MRI. Developmental Medicine and Child Neurology, 38(6), 496-502.
Lefebvre, F., Mazurier, E., & Tessier, R. (2005). Cognitive and educational outcomes in early adulthood for infants weighing 1000 grams or less at birth. Acta Paediatr, 94(6), 733-740.
Siegel, L. S. (1981). Infants tests as predictors of cognitive and language development at 2 years. Child Development, 52, 545-557.
Taylor, H. G., Klein, N., & Hack, M. (2000). School-age consequences of birth weight less than 750 g: a review and update. Dev Neuropsychol, 17(3), 289-321.
Vohr, B. R., Wright, L. L., Dusick, A. M., Mele, L., Verter, J., Steichen, J. J., 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).
Wechsler, D. (1981). Wechsler Abbreviated Scale of Intelligence - Revised. San Antonio, TX: The Psychological Corporation.
Whitfield, M. F., Grunau, R. E., & Holsti, L. (1997). Extremely premature (<=800 g) schoolchildren: multiple areas of hidden disability. Archives of Disease in Childhood, 77(2), F85-F90.