Amniotic Fluid is Swallowed by the Fetus and Excreted by the Kidneys
Babies that develop in mothers’ wombs are surrounded by amniotic fluid. Amniotic fluid, consisting mainly of water, is secreted by the amnion, in which the fetus floats and is protected from external pressure. It is swallowed by the fetus and excreted by the kidneys back into the amniotic sac. Some of the fluid swallowed by the fetus is absorbed through its intestine. About 1 liter of fluid is present at the 38th week of gestation. It protects the fetus from temperature variations and physical trauma and permits fetal movement. The amniotic sac normally ruptures in early labour to release the fluid (the ‘waters’).