Is it ensure, insure, or assure?
1590s, from French confinement (16c.; the Old French word was confinacion), from confiner (see confine). As a euphemism for "childbed" it dates from 1774 (the Middle English expression was Our Lady's bands).
confinement con·fine·ment (kən-fīn'mənt)
The act of restricting or the state of being restricted in movement.