The relationship of birth weight and birth weight discordance to cerebral palsy or mental retardation later in life for twins weighing less than 2500 grams

This is a study concerning all twins born in Sweden between 1973 and 1980 having a birth weight <2500 grams, (n=5,382). 115 twins with cerebral palsy or mental retardation were identified at age 8 years. The most interesting finding is that the larger twin in the pair had a significantly higher incidence of cerebral palsy than the smaller one did (relative risk 2.6, 95% confidence interval 1.4 to 4.8). The great majority of twins with a birth weight smaller than 2500 grams who later became disabled were appropriate for gestational age at birth.