Caffeine consumption during pregnancy and risk of preterm birth: a meta-analysis

Abstract

Background: The effect of caffeine intake during pregnancy on the risk of preterm delivery has been studied for the past 3 decades with inconsistent results.

Objective: We performed a meta-analysis examining the association between caffeine consumption during pregnancy and risk of preterm birth.

Design: We searched MEDLINE and EMBASE articles published between 1966 and July 2010, cross-referenced reference lists of the retrieved articles, and identified 15 cohort and 7 case-control studies that met inclusion criteria for this meta-analysis.

Results: The combined odds ratios (ORs) obtained by using fixed-effects models for cohort studies were 1.11 (95% CI: 0.96, 1.28), 1.10 (95% CI: 1.01, 1.19), and 1.08 (95% CI: 0.93, 1.27) for risk of preterm birth comparing the highest with the lowest level of caffeine intake (or no intake) (mg/d) during the first, second, and third trimesters, respectively. Results for the case-control studies yielded no associations for the first (OR: 1.07; 95% CI: 0.84, 1.37), second (OR: 1.17; 95% CI: 0.94, 1.45), or third (OR: 0.94; 95% CI: 0.79, 1.12) trimesters. No overall heterogeneity was found by region, publication decade, exposure and outcome assessment, caffeine sources, or adjustment for confounding, which was largely driven by individual studies.

Conclusion: In this meta-analysis, we observed no important association between caffeine intake during pregnancy and the risk of preterm birth for cohort and case-control studies.

FIGURE 1

Literature search results for publications related to caffeine consumption during pregnancy and the risk of preterm delivery. Studies were excluded on the basis of study design, absence of control subjects, no measures of association, and no definition or reporting of the required exposure (caffeine intake) outcome of interest.

FIGURE 2

Odds ratios from cohort studies estimating the association between prenatal caffeine consumption (highest compared with lowest intake) in the first, second, and third trimesters and preterm birth. Squares indicate study-specific estimates, horizontal lines indicate the 95% CIs, and diamonds indicate the summary estimate of the odds ratio with its corresponding 95% CI. ES, effect size; ID, identification.

FIGURE 3

Odds ratios from case-control studies estimating the association between prenatal caffeine consumption (highest compared with lowest intake) in the first, second, and third trimesters and preterm birth. Squares indicate study-specific estimates, horizontal lines indicate the 95% CIs, and diamonds indicate the summary estimate of the odds ratio with its corresponding 95% CI. ES, effect size; ID, identification.