Epidemiological analysis of microtia: a retrospective study in 345 patients in China.

OBJECTIVE

To study the epidemiologic characteristics of microtia in China and to investigate the possible risk factors with respect to the classification of microtia.

METHODS

A total of 345 patients with microtia were studied. All patients were taken an intentional physical examination and classified into five types. A detailed questionnaire concerning the maternal conditions during pregnancy was filled out by patient's mother. The frequencies of the relative factors were counted and the variables were statistically analyzed using Chi Square and Fisher's tests in the five types of microtia.

RESULTS

Most cases of microtia (88.12%) were sporadic and 72.75% of all cases occurred in males. It was more seen unilateral, especially affected on the right side (55.94%). A total of 195 patients (56.52%) were isolated microtia. In the rest of non-isolated microtia patients, 37.97% of the cases had hemifacial microsomia, which was the most common associated deformity. Thirty-four patients (9.86%) belonged to typical familial microtia. Three maternal factors showed significant differences in the five types of microtia, which were perinatal virus infection, high prior miscarriages and prevention treatments for threatened abortion.

CONCLUSIONS

The majority of microtia cases in China are sporadic and usually more common in males. Mothers who have prior miscarriages over 3 times or perinatal virus infection seem to be more likely to have severe microtia infants.