amnioinfusion

noun

am·​nio·​in·​fu·​sion ˌam-nē-ō-in-ˈfyü-zhən 

: the introduction of sterile saline or lactated Ringer's solution into the amniotic cavity via the uterine cervix typically during labor especially to increase the volume of amniotic fluid

Amnioinfusion relieves variable decelerations of the fetal heart, which are common after rupture of the membranes and are caused by intermittent compression of the umbilical cord during contractions.

—Bonnie Ennis Cox, Childbirth Instructor