[Catecholamine conjugation during pregnancy]

Conjugated urinary catecholamines are increased during normal human pregnancy. The modification in the proportions of conjugated fractions are particularly significant for norepinephrine. They depend on the foetoplacental unit since delivery is followed by a reduction of the urinary concentrations of these conjugated fractions. Such a modification of catecholamine metabolism must be kept in mind when the level of sympathetic nervous system activity is studied during pregnancy.