[Prevalence of Down syndrome using certificates of live births and fetal deaths in México 2008-2011].

BACKGROUND: Down syndrome (DS) or trisomy 21 is the most common genetic cause of mental retardation with the clinical presentation of a series of well-defined characteristics. Advanced maternal age has been associated with DS. METHODS: The databases of all the certificates of live births and fetal deaths in Mexico were combined. Codes based on the International Classification of Diseases 10th Revision (ICD-10) in Chapter XVII "Congenital malformations, deformations and chromosomal abnormalities" were selected. RESULTS: A database of 8,250,375 births during the period 2008-2011 was constructed: 99.2% were live births with 0.8% of fetal deaths and 3,076 cases diagnosed with DS. CONCLUSIONS: The importance of this report is to initiate an epidemiological surveillance of newborn cases of DS nationwide and by state using census information systems available in the country since 2008. An increased risk has been observed for having a child with DS since the mother is ≥ 35 years, as has been reported in other studies.