Of many exogenous causes, difficult birth, neonatal asphyxia, and coiling of the umbilical cord might be identified as risk factors predicting an initial febrile convulsion. Children with febrile convulsions and exogenous causes are likely to have affected family members, and have a risk of recurrence of seizures on 5 occasions or more. Exogenous causes alone barely raise the risk of recurrence of febrile convulsions after 3 years of age or development of afebrile convulsions. The incidence of exogenous causes is highest in children who develop afebrile convulsions after febrile convulsions, and lowest in children who experience only febrile convulsions, although a little higher than in normal controls.