爸妈你们知道羊水吗？Parents Must Know Fact 2

爸妈你们知道吗？Parents Must Know Fact 2

羊水，是指怀孕时子宫羊膜腔内的液体。在整个怀孕过程中，它是维持胎儿生命所不可缺少的重要成分。在胎儿的不同发育阶段，羊水的来源也各不相同。在妊娠第一个三月期，羊水主要来自胚胎的血浆成分；之后，随着胚胎的器官开始成熟发育，其他诸如胎儿的尿液、呼吸系统、胃肠道、脐带、胎盘表面等等，也都成为了羊水的来源。

Amniotic fluid [AF] amniotic fluid is positively correlated with the growth of fetus. From the 10th to the 20th week it increases from 25ml to 400ml approximately. From the 8th week, when the fetal kidneys begin to function, fetal urine is also present in the AF. Approximately in the 10th week the breathing and swallowing of the fetus slightly decrease the amount of AF, but neither urination nor swallowing contributes significantly to AF quantity changes, until the 25 week, when keratinization of skin is complete. Then the relationship between AF and fetal growth stops. It reaches the plateau of 800ml at the 28 week (gestational age). The amount of fluid declines to roughly 400 ml at 42 weeks ga.