Motor Impairment Trends in Extremely Preterm Children: 1991–2005

Abstract

BACKGROUND: There are increasing numbers of surviving children who were born extremely preterm (EP; gestational age <28 weeks) or extremely low birth weight (ELBW; birth weight <1000 g). Our objective in this study was to compare the rates of motor impairment at 8 years of age between 3 cohorts of EP and/or ELBW and term-born children to establish if motor impairment rates are changing over time. METHODS: All children born EP and/or ELBW in the calendar years of 1991–1992, 1997, and 2005 in Victoria, Australia, were recruited at birth. Randomly selected normal birth weight (>2499 g) and term-born controls were matched for expected date of birth, sex, and sociodemographic status. At 8 years’ corrected age, motor impairment was defined as cerebral palsy (CP) or a score less than the fifth centile on the Movement Assessment Battery for Children for the 1991–1992 and 1997 cohorts and less than or equal to the fifth centile on the Movement Assessment Battery for Children–Second Edition for the 2005 cohort. RESULTS: Motor impairment was more likely in children born EP and/or ELBW compared with children born at term for all epochs. There was a significant increase in motor impairment in EP and/or ELBW children over the 3 eras, from 23% in 1991–1992 and 26% in 1997 to 37% in 2005 (χ2trend = 10.2; P = .001). This was due to an increase in non-CP motor impairment (13% in 1991 to 1992; 15% in 1997; 26% in 2005; χ2trend = 12.5; P < .001), not CP (11% in 1991 to 1992; 11% in 1997; 12% in 2005). CONCLUSIONS: The rate of motor impairment in EP and/or ELBW children assessed at 8 years of age increased between eras, an increase caused by non-CP motor impairment.