Amnioreduction

Amnioreduction is a percutaneous medical procedure in which a portion of amniotic fluid is removed from the amniotic sac under ultrasound guidance. It is used to treat polyhydramnios, a condition characterized by excess amniotic fluid, and in the management of twin-to-twin transfusion syndrome (TTTS) as a method to decompress the recipient twin’s amniotic cavity.

The procedure is performed by inserting a fine needle or cannula through the maternal abdomen into the uterus to access the amniotic sac, using sterile technique and real-time ultrasound to avoid injury. Fluid is removed in small aliquots to reduce distention gradually and to minimize rapid shifts in intrauterine pressure. The goal is often to decrease the amniotic fluid index or deepest vertical pocket to target values, relieve maternal symptoms, and lower the risk of preterm contractions and placental crowding. After the procedure, fetal monitoring is typically continued for several hours, and additional amnioreductions may be required if polyhydramnios recurs.

Risks include preterm labor, uterine contractions, bleeding, infection, placental abruption, leakage of amniotic fluid, fetal distress, and, rarely, injury to the fetus or uterus. Amnioreduction is generally considered when the expected benefits outweigh the risks and is often performed when other management options are limited. The procedure has a long history in obstetric care, with refinements in technique and guidance improving safety.