Tone refers to a lack of uterine tone or uterine atony – basically a soft, spongy, boggy uterus, and this is the main cause of postpartum hemorrhage, generally resulting in a slow and steady loss of blood.
Tone代指子宫张力缺乏或子宫乏力,也就是柔软的、海绵状的、水肿的子宫,这是产后出血的最主要原因,一般引起缓慢持续的血液丢失。