[Frequency of congenital defects in Spain: 1976-1983].

The Spanish Collaborative Study of Congenital Malformations (ECEMC) has analyzed 414,434 newborns in 45 hospitals in the last eight years (1976-1983). Amongst them 8,272 showed some birth defect detectable within the three first days of life (2%). A study on the incidence of birth defects classified according to their presentation in the newborn is carried out. We try to show importance of doing a careful clinical analysis of the cases in order to form groups as much homogeneous as possible from an etiopathogenic point of view. This is an essential requirement to approach with guarantees any epidemiological analysis. We also show the results of the epidemiological surveillance performed over 15 birth defects during the years 1981, 1982 and 1983.