[Preauricular tags: prevalence, clinical characteristics and maternal risk factors]

To determine prevalence and maternal risk factors associated with preauricular tags.

A case-control study of 254 newborns with isolated preauricular tags not considered part of a syndrome and their controls, and who were delivered at the Hospital Civil de Guadalajara Dr. Juan I. Menchaca between 1990 and 2003. The maternal risk factors were demonstrated by means of a direct interview with the mother.

The prevalence of the isolated preauricular tags was 1.96 per 1,000 newborns alive, in a 1.2 men for each woman. The history of another affected relative was strongly associated with preauricular tags (OR 19.28; 95% CI: 4.44-117.60). Infants with preauricular tags frequently showed parents consanguinity (OR 3.04; 95% CI: 0.28-76.26), maternal age > or =35 years (OR 1.14; 95% CI: 0.53-2.48), exposure to some disease (OR: 1.23, 95% CI: 0.72-2.12), and drugs use in the first trimester of pregnancy (OR: 1.11; 95% CI: 0.65-1.92). No associations were found for the frequency of abortion, exposure to organic solvents and maternal occupation.

The prevalence of isolated preauricular tags in this population was similar to that reported in other regions of Latin America, but lower to the prevalences in Sweden and Israel. This malformation has an important hereditary component; however, it is probably that some teratogenic factors, such as diabetes mellitus, can increase its frequency.