"the first milk secreted in the breasts after childbirth," 1570s, from Latin colostrum "first milk from an animal," earlier colustra, a word of unknown etymology.
"confinement during and after childbirth," 1863, from Latin puerperus (see puerperal). From c. 1600 in navitized form puerpery.
early 15c., "act of setting free from bondage," also "action of handing over to another," from Anglo-French delivrée, noun use of fem. past participle of Old French delivrer (see deliver). Sense of "childbirth, giving forth of offspring" is by 1570s; that of "manner of utterance or enunciation" is from 1660s. Of a blow, throw of a ball, etc., "act of sending or putting forth," from 1702. The hospital's childbirth delivery room is attested by 1849 (in early use often in a German context, translating Kreisszimmer).
1620s, "state of being confined; any restraint by force, necessity, or obstacle," from French confinement (16c.; the Old French word was confinacion), from confiner "to border; to shut up, enclose" (see confine).
As "restraint from going abroad by childbirth," perhaps a euphemism for childbed it dates from 1774 (the Middle English expression was Our Lady's bands). To be confined "be unable to leave the house or bed from sickness or childbirth" is attested from 1772.