The objective was that of evaluating the efficacy of amnioreduction in improving the principal complications given by polyhydramnios such as maternal dyspnea and uterine activity. [ncbi.nlm.nih.gov]

[…] polyhydramnios in singleton pregnancies be defined as either a deepest vertical pocket of
8 cm or an amniotic fluid index of
24 cm (GRADE 2C); (2) we recommend that amnioreduction be considered only for the indication of severe maternal discomfort, dyspnea [smfm.org]

In the mother, the physician may observe increased abdominal size out of proportion for her weight gain and gestation age, uterine size that outpaces gestational age, shiny skin with stria (seen mostly in severe polyhydramnios), dyspnea, and chest heaviness [en.wikipedia.org]

30 moderate: single deepest pocket at 12-15 cm or AFI 30.1-35 severe: single deepest pocket 16 cm or AFI 35 The risk of the following obstetric complications is increased when polyhydramnios is present due to over-expansion of the uterus13: maternal dyspnea [radiopaedia.org]

A 1900-g baby girl born at 36 weeks' gestation presented with bilateral wide facial clefts with macrostomia, microphthalmia, nose, and auricular deformities. Her breathing was dependent on life support, which was discontinued 2 hours after birth. [ncbi.nlm.nih.gov]

The procedure not only decompressed the lung cyst but also improved the secondary physiological changes, i.e. mediastinal shift, hydrops and polyhydramnios. [ncbi.nlm.nih.gov]