Comparison of maternal and fetal blood levels of caffeine and its metabolite. A pilot study

Abstract

Objective: The aim of the study was to compare caffeine and paraxanthine concentrations in venous blood of pregnant women and in the umbilical cord blood of their newborns. Materials and Methods: Pregnant women who gave birth at the Clinic of Obstetrics, Gynecology and Oncology, 2nd Faculty of Medicine, Medical University of Warsaw were included in the study. Caffeine and paraxanthine concentrations were analyzed in 30 samples of venous blood serum drawn from the women before delivery and 30 samples of umbilical cord blood serum of their newborns. Caffeine intake in the last 24 hours before delivery was estimated using a questionnaire. Statistical analysis employed a linear logistic regression model, Wilcoxon rank sum test and a non-parametric Spearman’s rank correlation coefficient. Results: No difference was found between caffeine concentration in maternal venous blood and neonatal umbilical cord blood. However, paraxanthine level in venous blood was higher than in umbilical cord blood (p = 0.04). Conclusions: Caffeine consumed by a pregnant woman passes through the placenta to the fetus freely.