Polyhydramnios: Excessive Accumulation of Amniotic Fluid

-1. Normal Regulation of Amniotic Fluid

At the beginning of a pregnancy, amniotic fluid is mostly composed of water that comes from the mother. Later, at around 20 weeks, the fluid is primarily fetal urine. The amount is regulated by the fetus swallowing the fluid and passing it back into the amniotic sac as urine. Polyhydramnios, or too much amniotic fluid, occurs for several reasons, particularly when this method of regulation is not effective.