amniocentesis /-sin-tēˈsis/ noun (pl amniocenteˈses /-sēz/)

The insertion of a hollow needle into the uterus of a pregnant woman to withdraw a sample of the amniotic fluid to test for fetal abnormalities, etc (informal short form amˈnio)

amniotomy /-otˈ/ noun

Surgical rupture of the amnion during, or in order to induce, labour