title: The incidence and etiology of postpartum headaches: a prospective cohort study.
abstract: OBJECTIVE
  We sought to determine the incidence, etiology, characteristics and risk factors for all headaches in the first week postpartum.
  
  
  METHODS
  This was a prospective cohort study of 985 women delivering over a three-month period in a single tertiary-care institution. These women underwent a structured interview and follow-up to collect demographic data and to assess for the presence and characteristics of postpartum headache (PPHa) or neck/shoulder pain. All headaches were diagnosed using an algorithm based on the diagnostic criteria of the International Headache Society. Multivariate analysis was used to examine possible risk factors.
  
  
  RESULTS
  Three hundred eighty-one of the 985 study participants (39%) reported headaches or neck/shoulder pain during the study period. The median time to onset of the PPHa was two days (0, 6; 1st and 3rd quartiles) and duration was four hours (2, 24; 1st and 3rd quartiles). Primary headaches accounted for > 75% of PPHa. Only a small number of headaches (4%) were incapacitating. Postdural puncture headache accounted for 4.7% of all PPHa. Significant risk factors for the development of PPHa were: known inadvertent dural puncture [odds ratio (OR)adj = 6.36; 95% confidence interval (CI) 1.29, 31.24]; previous headache history (1-12/yr-OR(adj) = 1.57; 95% CI 1.01, 2.44; > 12/yr-OR(adj) = 2.25; 95% CI 1.63, 3.11); multiparity (OR(adj) = 1.37; 95% CI 1.03, 1.82) and increasing age (OR(adj) = 1.03/yr; 95% CI 1.00, 1.06).
  
  
  CONCLUSIONS
  Postpartum headaches are common, often first noted after discharge from hospital. The majority are related to primary headache disorders. Increased awareness of this epidemiological relationship and improved diagnosis of primary headache conditions may lead to improved headache-specific therapy and avoidance of unnecessary investigations or read-mission to hospital.
authors.affiliation: Department of Anesthesia, Mount Sinai Hospital, Toronto, Ontario, Canada. e.goldszmidt@utoronto.ca
authors.forename: Eric
authors.initials: E
authors.lastname: Goldszmidt
authors.forename: Ralph
authors.initials: R
authors.lastname: Kern
authors.forename: Alan
authors.initials: A
authors.lastname: Chaput
authors.forename: Alison
authors.initials: A
authors.lastname: Macarthur
mesh_terms: D000328:Adult; D000367:Age Factors; D000465:Algorithms; D016022:Case-Control Studies; D015331:Cohort Studies; D005006:Ethnicity; D005260:Female; D006261:Headache / Q000145:classification / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015999:Multivariate Analysis; D019547:Neck Pain / Q000453:epidemiology / Q000209:etiology; D016017:Odds Ratio; D010298:Parity; D049590:Postpartum Period; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D018401:Sample Size; D020069:Shoulder Pain / Q000453:epidemiology / Q000209:etiology; D013129:Spinal Puncture / Q000009:adverse effects