Some of the known causes of polyhydramnios include:

  • A birth defect that affects the baby's gastrointestinal tract or central nervous system
  • Maternal diabetes
  • Twin-twin transfusion — a possible complication of identical twin pregnancies in which one twin receives too much blood and the other too little
  • A lack of red blood cells in the baby (fetal anemia)
  • Blood incompatibilities between mother and baby

Often, however, the cause of polyhydramnios isn't clear.

Oct. 25, 2014

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