Segmental epidural analgesia and urinary excretion of catecholamines during labour.

Urinary excretion of catecholamines was determined separately during the first stage of labour and during the period from the beginning of the second stage until 1/2 h after delivery in 16 healthy mothers, whose labours were induced at term. Seven mothers were given segmental epidural analgesia, at the height of TH10-12, to achieve complete pain relief during the first stages of labour. The remaining parturients served as controls. During the first stage of labour the urinary excretion rate of catecholamines was at the normal nongravid rest level in both groups. During the second stage, and 1/2 h after the delivery, the amount of urinary catecholamines increased significantly in both groups. The latter values corresponded to the amounts of catecholamines excreted during heavy physicial work.