title: Maternal caffeine consumption during pregnancy and the risk of miscarriage: a prospective cohort study.
abstract: OBJECTIVE
  The objective of the study was to examine whether the risk of miscarriage is associated with caffeine consumption during pregnancy after controlling for pregnancy-related symptoms.
  
  
  METHODS
  This was a population-based prospective cohort study.
  
  
  RESULTS
  An increasing dose of daily caffeine intake during pregnancy was associated with an increased risk of miscarriage, compared with no caffeine intake, with an adjusted hazard ratio (aHR) of 1.42 (95% confidence interval 0.93 to 2.15) for caffeine intake of less than 200 mg/day, and aHR of 2.23 (1.34 to 3.69) for intake of 200 or more mg/day, respectively. Nausea or vomiting during pregnancy did not materially affect this observed association, nor did the change in intake pattern of caffeine during pregnancy. In addition, the magnitude of the association appeared to be stronger among women without a history of miscarriage (aHR 2.33, 1.48 to 3.67) than that among women with such a history (aHR 0.81, 0.34 to 1.94).
  
  
  CONCLUSIONS
  Our results demonstrated that high doses of caffeine intake during pregnancy increase the risk of miscarriage, independent of pregnancy-related symptoms.
authors.affiliation: Division of Research, Kaiser Permanente, Oakland, CA 94612, USA.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Weng
authors.forename: Roxana
authors.initials: R
authors.lastname: Odouli
authors.forename: De-Kun
authors.initials: DK
authors.lastname: Li
mesh_terms: D000022:Abortion, Spontaneous / Q000139:chemically induced* / Q000453:epidemiology*; D000328:Adult; D001628:Beverages; D002110:Caffeine / Q000009:adverse effects*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D002110:Caffeine