Prenatal caffeine assessment: fetal and maternal biomarkers or self-reported intake?

Ann Epidemiol. 2008 Mar;18(3):172-8. doi: 10.1016/j.annepidem.2007.11.005.


Purpose: We sought to examine associations among measures of caffeine exposure, including maternal urine, umbilical cord blood, and maternal self report.

Methods: Pregnant women were recruited from 56 obstetric practices and 15 clinics associated with six hospitals in Connecticut and Massachusetts between September 1996 and January 2000; 3633 women were enrolled. Maternal urine throughout pregnancy and umbilical cord blood samples were analyzed for caffeine, paraxanthine, theophylline, and theobromine. Maternal caffeine intake was assessed throughout pregnancy.

Results: Urinary and cord blood biomarkers were correlated with reported intake throughout pregnancy (range r = 0.35-0.66; p < 0.0001). Infants of smokers had greater cord blood concentrations of paraxanthine, reflecting faster caffeine metabolism in smokers, and cord blood paraxanthine levels were more strongly correlated with intake in smokers.

Conclusion: Maternal self reported intake may still be the optimal and most valid measure of antenatal caffeine exposure, since biomarkers do not reflect exposure over pregnancy.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Biomarkers / blood
  • Biomarkers / urine
  • Caffeine / administration & dosage*
  • Caffeine / blood
  • Caffeine / urine
  • Connecticut
  • Female
  • Fetal Blood / metabolism
  • Humans
  • Massachusetts
  • Maternal-Fetal Exchange
  • Mothers*
  • Pregnancy / blood
  • Pregnancy / urine
  • Pregnancy Outcome


  • Biomarkers
  • Caffeine