Cardiac troponin T and amino-terminal pro-natriuretic peptide concentrations in fetuses in the second trimester and in healthy neonates.

We measured the concentrations of cardiac troponin T (cTnT) and amino-terminal pro-natriuretic peptide (NT-proBNP) in umbilical cord blood during the second trimester (20–25 weeks of gestation) and at delivery in 109 uncomplicated pregnancies to define reference values. Using the 97.5th percentile, the upper reference limits for cTnT and NT-proBNP were 0.308 ng/mL and 5402 pg/mL in fetuses in the second trimester, and 0.038 ng/mL and 1690 pg/mL in healthy neonates, respectively. We also evaluated whether labor and delivery mode affected the concentrations of the two analytes. We found significantly higher (p<0.001) umbilical blood NT-proBNP and cTnT levels at 20–25 weeks of gestation than at term. In addition, within the term group, NT-proBNP concentrations were significantly higher in women delivering by elective cesarean section than in women delivering spontaneously (p<0.001), and higher than in women delivering by cesarean section during active labor. This indicates that the decrease in NT-proBNP levels is probably due to labor rather than delivery mode. Finally, we confirmed the at-birth reference values previously established for cTnT and NT-proBNP. Clin Chem Lab Med 2006;44:834–6. [ABSTRACT FROM AUTHOR]