Urinary metabolites of caffeine in pregnant women

Br J Clin Pharmacol. 1986 Oct;22(4):475-8. doi: 10.1111/j.1365-2125.1986.tb02920.x.


In a study of caffeine and its metabolites in pregnant and non-pregnant women, on average 56.8% of the administered caffeine dose was recovered in the urine in both groups. However, compared to the controls, the pregnant subjects produced smaller amounts of 1-methylxanthine and 1-methyluric acid, whereas the excretion of most of the other metabolites, particularly 3,7-dimethylxanthine and 3-methylxanthine tended to be greater. It is suggested that hormonal influences on the hepatic caffeine metabolising enzymes might be implicated.

MeSH terms

  • Caffeine / metabolism*
  • Female
  • Humans
  • Pregnancy / metabolism*
  • Theophylline / urine
  • Uric Acid / analogs & derivatives
  • Uric Acid / urine
  • Xanthines / urine


  • Xanthines
  • Uric Acid
  • methylxanthine
  • 1-methyluric acid
  • Caffeine
  • Theophylline
  • 1,7-dimethylxanthine
  • 3-methylxanthine