Maternal Risk Factors for Severe Microtia/atresia in China: A Case-control Study

Objective: Microtia/atresia is a severe malformation of the external ear. Previous studies have reported the potential risk factors on microtia, whereas few focused on severe microtia/atresia. The aim of the study was to investigate the effects of maternal exposure to environmental risk factors in patients with severe microtia/atresia in China.

Methods: A case-control study was conducted. Cases were patients with severe microtia/atresia who presented to PUMCH between January 2014 and October 2017. A total of 322 patients with severe microtia/atresia were enrolled and 322 normal controls matched 1:1 with the patients by sex, age and nationality were enrolled. The designed questionnaires were completed and data were gathered. Odds ratios were estimated with logistic regression models along with 95% confidence intervals in severe microtia/atresia.

Results: Most cases were males(68.6%), and the cases were observed more common in unilateral(80.7%), right-sided (54.0%). Multivariate logistic regression analysis showed that threatened abortion (OR 4.066,95% CI = 2.360-7.007), NSAIDs (OR 2.576,95% CI = 1.079-6.148), virus infection (OR 1.933,95% CI = 1.148-3.256), anemia (OR 1.902,95% CI = 1.026-3.526), miscarriages (OR 1.804,95% CI = 1.425-2.285), maternal age (OR 1.079,95% CI = 1.015-1.148) and paternal age (OR 1.061,95% CI = 1.003-1.122) were associated with a higher risk of severe microtia/atresia.

Conclusion: These results support that some maternal risk factors could be associated with severe microtia/atresia.