Polyhydramnios is too much fluid in the amniotic sac. The amniotic sac is the water bag inside the uterus that cushions and protects your baby. It also allows normal growth and development to occur. Normal amniotic fluid levels vary. The average volume during pregnancy is almost one liter at 36-37 weeks. In severe cases, the condition can result in:

Fetus in Utero, Amniotic Fluid
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In most cases, the cause of polyhydramnios is not known. In others, causes may include:

  • Birth defects
  • Rh disease—a treatable condition that occurs when mother and baby have different blood types
  • Diabetes in the mother
  • Identical twins