title: A meta-analysis of risk of pregnancy loss and caffeine and coffee consumption during pregnancy.
abstract: BACKGROUND
  Previous reports of the relationship between pregnancy loss and caffeine/coffee consumption have been inconsistent.
  
  
  OBJECTIVE
  To evaluate the association between pregnancy loss and caffeine and coffee consumption.
  
  
  METHODS
  PubMed was searched for reports published before September 2014, with the keywords "caffeine," "coffee," "beverage," "miscarriage," "spontaneous abortion," and "fetal loss."
  
  
  METHODS
  Case-control and cohort studies were included when they had been reported in English, the exposure of interest was caffeine/coffee consumption during pregnancy, the outcome of interest was spontaneous abortion or fetal death, and multivariate-adjusted odds ratios (ORs) or risk ratios were provided or could be calculated.
  
  
  METHODS
  Data were extracted and combined ORs calculated.
  
  
  RESULTS
  Overall, 26 studies were included (20 of caffeine and eight of coffee). After adjustment for heterogeneity, caffeine consumption was associated with an increased risk of pregnancy loss (OR 1.32, 95% confidence interval [CI] 1.24-1.40), as was coffee consumption (OR 1.11, 95% CI 1.02-1.21). A dose-response analysis suggested that risk of pregnancy loss rose by 19% for every increase in caffeine intake of 150 mg/day and by 8% for every increase in coffee intake of two cups per day.
  
  
  CONCLUSIONS
  Consumption of caffeine and coffee during pregnancy seems to increase the risk of pregnancy loss.
authors.affiliation: Center for Health Management, School of Health Services Management, Anhui Medical University, Hefei, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Nutrition, Jiangsu Province Traditional Chinese Medicine Hospital, Nanjing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Social Medicine and Health Services Management, School of Public Health, Kunming Medical University, Kunming, China.
authors.forename: Ju-Min
authors.initials: JM
authors.lastname: Song
authors.affiliation: Second Affiliated Hospital of Anhui Medical University, Hefei, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Rehabilitation Medicine, The Affiliated Provincial Hospital of Anhui Medical University, Hefei, China.
authors.forename: Yin-Lan
authors.initials: YL
authors.lastname: Tang
authors.affiliation: Center for Health Management, School of Health Services Management, Anhui Medical University, Hefei, China. Electronic address: xinchangmao@ahmu.edu.cn.
authors.forename: Chang-Mao
authors.initials: CM
authors.lastname: Xin
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology* / Q000209:etiology; D002110:Caffeine / Q000008:administration & dosage / Q000009:adverse effects*; D003069:Coffee / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D011247:Pregnancy; D012306:Risk
chemical_list: D003069:Coffee; D002110:Caffeine
keywords: Caffeine; Coffee; Fetal death; Meta-analysis; Pregnancy loss; Spontaneous abortion