title: The "Christmas Effect" and other biometeorologic influences on childbearing and the health of women.
abstract: OBJECTIVE
  To review the body of literature addressing biometeorologic and chronobiologic effects on conception, pregnancy, parturition, and other health conditions.
  
  
  METHODS
  Computerized searches of MEDLINE, PUBMED, CINAHL, and the World Wide Web.
  
  
  METHODS
  Studies, including international research, dating from 1938 to 2001.
  
  
  METHODS
  Data were extracted and information organized under the following categories: influence of leisure time and seasonality on the rate of conception and birth, the relationship of meteorologic changes and lunar cycles to childbearing, the "Christmas Effect" and its impact on other health outcomes, and nursing implications.
  
  
  RESULTS
  Research from the disciplines of biometeorology and chronobiology indicates that there are patterns in the occurrence of conception, pregnancy, and onset of labor that vary in timing and amplitude in different populations and geographic regions. Consideration of these factors should be included in the analysis of birth data when planning and providing maternity care. The Christmas Effect is one of the most predominant seasonal patterns that can be seen in birth data throughout the world.
  
  
  CONCLUSIONS
  Biometeorologic and other cyclic phenomena are underused in the United States in planning and providing maternity care. These phenomena warrant consideration when planning holistic health care.
mesh_terms: D001723:Birth Rate; D002909:Chronobiology Phenomena; D005260:Female; D006285:Health Planning; D006693:Holidays; D006801:Humans; D007231:Infant, Newborn; D007743:Labor, Obstetric; D007899:Leisure Activities; D008685:Meteorological Concepts; D016081:Moon; D011247:Pregnancy; D012098:Reproduction; D012621:Seasons; D016387:Women's Health