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.

Objectives: To evaluate the association between pregnancy loss and caffeine and coffee consumption.

Search strategy: PubMed was searched for reports published before September 2014, with the keywords "caffeine," "coffee," "beverage," "miscarriage," "spontaneous abortion," and "fetal loss."

Selection criteria: 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.

Data collection and analysis: Data were extracted and combined ORs calculated.

Main 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.

Keywords: Caffeine; Coffee; Fetal death; Meta-analysis; Pregnancy loss; Spontaneous abortion.