The changing panorama of cerebral palsy in Sweden. VII. Prevalence and origin in the birth year period 1987-90.

This seventh Swedish population-based cerebral palsy (CP) report comprises 216 children born between 1987 and 1990. The crude live birth prevalence was 2.36 per 1000, indicating a break in the continuous increase since 1970. Excluding 10 postnatally-derived cases, gestational-age specific prevalences were 80 for extremely, 54 for very and 8 for moderately preterms and 1.4 for term children per 1000. Birth weight-specific prevalences were 57 for birth weights < 1000 g, 68 for 1000-1499 g, 14 for 1500-2499 g and 1.4 for > or = 2500 g per 1000. The aetiology was considered prenatal in 8%, peri/neonatal in 54% and unclassifiable in 38% of preterms and 33, 28 and 39% of term children. Hemiplegic, diplegic and tetraplegic syndromes accounted for 22, 66 and 7% of preterms and 44, 29 and 10% of term children. Non-walking, mental retardation, epilepsy, severe visual impairment and infantile hydrocephalus were present in 39, 39, 26, 18 and 23% of preterms; and 38, 44, 36, 14 and 5% of term children, respectively. The entire series of 1408 cases born in 1954-90 revealed three distinct trend eras for preterms, clearly related to changes in perinatal care and shifts in type of CP manifestations.