title: Relationship between lunar cycle and haemorrhagic complication rate in surgery.
abstract: BACKGROUND
  The aim of this study was to evaluate a possible relationship between lunar cycles and haemorrhagic complication rate in surgery.
  
  
  METHODS
  The possible relationship between moon phases and surgical outcome was tested by evaluating the haemorrhagic complication rate for 18,760 patients who underwent surgery between January 2001 and December 2008 at the National Institute for Cancer Research in Genoa. A total of 103 lunar phases were considered using Chi-square (χ2) test analysis, and patients were allocated a surgery date.
  
  
  RESULTS
  One hundred and sixty-seven haemorrhagic complications were observed. Three hundred and nine new moon phase days were analysed and 12 incidences of complications detected, with a 3.9% complication rate per day. In the waxing moon phase, 1184.5 d were analysed with 68 incidences of complications at a daily rate of 5.7%. In the full moon phase there was a 4.9% complication rate per day (15 incidences in 309 d), whereas in the waning moon phase, the 6% percentage rate per day resulted from 72 incidences in 1184.5 d.
  
  
  CONCLUSIONS
  No statistically significant correlations were found between moon cycles and postoperative haemorrhagic complications (p = .50).
authors.affiliation: a Department of Medicine and Surgery, Plastic Surgery Unit, University of Parma , Parma , Italy.|b Cutaneous, Mini-invasive, Regenerative and Plastic Surgery Section , Parma University Hospital , Parma , Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Raposio
authors.affiliation: a Department of Medicine and Surgery, Plastic Surgery Unit, University of Parma , Parma , Italy.|b Cutaneous, Mini-invasive, Regenerative and Plastic Surgery Section , Parma University Hospital , Parma , Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Caruana
authors.affiliation: c Department of Surgical and Integrated Methodological Sciences (DICMI) , University of Genova , Genova , Italy.
authors.forename: Pierluigi
authors.identifier: http://orcid.org/0000-0002-4127-3537
authors.initials: P
authors.lastname: Santi
authors.affiliation: d Surgical Oncology Department , IRCCS San Martino IST , Genova , Italy.
authors.forename: Ferdinando
authors.identifier: http://orcid.org/0000-0003-2085-1833
authors.initials: F
authors.lastname: Cafiero
mesh_terms: D000367:Age Factors; D000368:Aged; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy; D008297:Male; D008875:Middle Aged; D016081:Moon; D019106:Postoperative Hemorrhage / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors
keywords: Lunar cycles; haemorrhagic complications; surgery