Relief puncture refers to an amniotic fluid withdrawal for therapeutic reasosn, which becomes necessary when there is extreme formation of amniotic fluid, e.g. due to a fetal illness (e.g. swallowing disorders of the fetus in the context of oral floor tumors, diaphragmatic hernias, occlusion of the esophagus, etc.).
The procedure is similar to that of amniocentesis, only larger amounts of amniotic fluid are removed. The most common cause of polyhydramnios is an insufficiently adjusted or undetected gestational diabetes, of course there is no relief necessary here, but the diet is optimized accordingly.