Which of the following statements concerning polyhydramnios is true ?

Polyhydramnios is an excessive quantity of amniotic fluid. The incidence of associated malformation with it may range upto 15% of all cases Edema of the lower extremities, vulva, and abdominal wall can occur,resulting from compression of major venous systems. Acute polyhydramnios tends to occur early in pregnancy and by definition is accumulation of fluid more than 25 AFI prior to 24 weeks. This as a rule, leads to labor before the 28th week. The most frequent maternal complications are placental abruption, uterine dysfunction, and postpaum hemorrhage.