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Weng X, Odouli R, Li DK. 
“Maternal caffeine consumption during pregnancy and the risk of miscarriage: a prospective cohort study”. 
Am J Obstet Gynecol. 2008 Jan 28.
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. STUDY

DESIGN: 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). CONCLUSION: Our results demonstrated that high doses of caffeine intake during pregnancy increase the risk of miscarriage, independent of pregnancy-related symptoms.
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Apr 17, 2011 1:59
Science Reporting: Positive Findings vs. Negative Findings #

The same month this study was published, a similar study was published in the journal Epidemiology. While this study by Weng et al. found a statistically significant correlation between caffeine intake and miscarriage, the Epidemiology study found no significant correlation.

Weng et al., which found a correlation, received major media attention - reports aired on TV news and articles appeared in major print media including the New York Times. However, the study by Savitz et al. did not receive remotely comparable coverage. In fact, it was not even mentioned in several articles on caffeine and miscarriage that I reviewed following the publication of Weng et al., despite being published at the same time and being readily available through Medline.

This disparity in coverage may reflect a significant and widely-recognized problem with scientific research: positive findings generally receive much greater attention than negative findings.

The Epidemiology abstract may be viewed here:
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