Postpartum hemorrhage is an obstetric emergency and maintaining adequate circulating volume is a key priority.

产后出血是一种产科急症，维持充足的循环血量是首要原则。

During the delivery of an infant, some mothers can experience excessive blood loss, which is called postpartum hemorrhage.

在分娩过程中，一些孕妇会出现大量失血，称为产后出血。

Significant bleeding in the first 24 hours after delivery is called primary postpartum hemorrhage, and after that it's called secondary, or late, postpartum hemorrhage.

分娩后24小时以内的大量出血被定义为原发性产后出血，而发生在分娩24小时后的大量出血则被称为继发性（迟发型）产后出血。

The most common causes of postpartum hemorrhage can be lumped into four groups which can easily be remembered as the " 4 Ts" : Tone, Trauma, Tissue, and Thrombin.

造成产后出血的最常见的原因可以归结于以下4个方面：宫缩乏力、产道损伤、胎盘滞留和凝血功能障碍，可以简单地记忆为“4T”。

In Sheehan's syndrome, postpartum hemorrhage causes lactotrophs and other cells of the pituitary to die, resulting in low levels of prolactin, growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, luteinizing hormone, and follicle stimulating hormone.

在席汉综合征中，产后出血会导致泌乳细胞和垂体其他细胞的死亡，使得催乳素、生长激素、促甲状腺激素、促肾上腺皮质激素、黄体生成素和卵泡刺激素水平降低。

Alright, as a quick recap, postpartum hemorrhage is the most common cause of maternal morbidity and mortality around the world, and the causes are the 4 T's: Tone (atony), Trauma, Tissue, and Thrombus (coagulopathy).

好！快速回顾一下：产后出血是全世界孕产妇发病和死亡的最主要原因；其原因可归结为“4T”：宫缩乏力（Tone）、产道损伤（Trauma）、胎盘滞留（Tissue）与凝血功能障碍（Thrombus）。

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。

So additional criteria to consider for postpartum hemorrhage include a decrease of 10% or more in hematocrit from baseline, and changes in a mother's heart rate, blood pressure, and oxygen saturations - all of which suggest a significant blood loss.

产后出血的额外诊断标准还包括：红细胞比容下降10%以上以及母体心率、血压和血氧饱和度的变化，以上这些都提示有大量血液丢失。