A meta-analysis of risk of pregnancy loss and caffeine and coffee consumption during pregnancy

BackgroundPrevious reports of the relationship between pregnancy loss and caffeine/coffee consumption have been inconsistent.ObjectivesTo evaluate the association between pregnancy loss and caffeine and coffee consumption.Search strategyPubMed was searched for reports published before September 2014, with the keywords “caffeine,” “coffee,” “beverage,” “miscarriage,” “spontaneous abortion,” and “fetal loss.”Selection criteriaCase-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.Data collection and analysisData were extracted and combined ORs calculated.Main resultsOverall, 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.ConclusionsConsumption of caffeine and coffee during pregnancy seems to increase the risk of pregnancy loss.