title: [Frequency and trends of congenital defects in Spain: usefulness and significance of different frequencies].
authors.affiliation: Estudio Colaborativo Español de Malformaciones Congénitas (ECEMC), Facultad de Medicina, Universidad Complutense de Madrid. luisama@eucmos,sim.ucm.es
authors.forename: M L
authors.initials: ML
authors.lastname: Martínez-Frías
authors.forename: E
authors.initials: E
authors.lastname: Bermejo
mesh_terms: D000013:Congenital Abnormalities / Q000453:epidemiology*; D006801:Humans; D007231:Infant, Newborn; D015995:Prevalence; D013030:Spain / Q000453:epidemiology; D013997:Time Factors