Amniotic fluid is partly the child’s urine and partly composed of fluid secreted by the alveoli, the umbilical cord and fluid exuded from the skin. There is fetal urine in amniotic fluid, but not all of it. Early in pregnancy, amniotic fluid is mainly derived from the mother’s blood, which permeates the amniotic cavity due to pressure and becomes the initial amniotic fluid. As the embryo gradually develops and matures, the fetus begins to have kidney function, and there will be urine discharged. At this time, most of the amniotic fluid is fetal urine, and part of it is the fluid secreted by the alveoli, the umbilical cord, and the fluid produced by the skin. The main component of amniotic fluid is urine. In order to avoid the uterus from being distended, the amount of amniotic fluid has a dynamic equilibrium, and too much or too little amniotic fluid may affect the normal development of the fetus. Doing a good maternity test after pregnancy will also enable you to find out if the amount of amniotic fluid in the uterus is normal, and seek medical attention if there is any abnormality.