title: Seasonal variation in months of birth of patients with microtia in a Chinese population.
abstract: OBJECTIVE
  Seasonality in months of births has been found in many congenital deformities, but little data are available in microtia, especially in a Chinese population. The aim of this study was to determine whether births of patients with microtia follow a seasonal pattern in a Chinese population.
  
  
  METHODS
  Patients with microtia treated at the Plastic Surgery Hospital between 2009-03 and 2010-03 were investigated according to the months of births. Seasonal variations in months of births were analyzed by using χ(2) test.
  
  
  RESULTS
  A total of 693 patients with microtia were included in the study. Birth time peaks occurred in autumn and winter, especially in October and March, compared with the nadir in the summer (P<0.05). The birth time peaks of male occurred in autumn and winter, especially in October, January and September. The birth time peaks of female occurred in spring and summer, especially in March. There was statistical difference in birth distribution in different months (P<0.05) or four seasons (P<0.05) between the two genders. There was no statistical difference in birth distribution on a monthly or seasonal basis by sides.
  
  
  CONCLUSIONS
  The data indicate that there is a possible seasonality in months of births of patients with microtia in a Chinese population and a difference between the genders. This approach could be useful for the study of the etiology and pathogenesis of microtia.
authors: Plastic Surgery Hospital, Peking Union Medical College and Chinese Academy of Medical Science, Beijing, People's Republic of China.
authors: Lei
authors: L
authors: Liu
authors: Bo
authors: B
authors: Pan
authors: Lin
authors: L
authors: Lin
authors: Xiaobo
authors: X
authors: Yu
authors: Qinghua
authors: Q
authors: Yang
authors: Yanyong
authors: Y
authors: Zhao
authors: Hongxing
authors: H
authors: Zhuang
authors: Haiyue
authors: H
authors: Jiang
mesh_terms: D044466:Asian People; D001723:Birth Rate; D002681:China; D000013:Congenital Abnormalities / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery; D065817:Congenital Microtia; D004423:Ear / Q000002:abnormalities / Q000601:surgery; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons; D017678:Sex Distribution