In the article examines are the function, language and distribution of childbirth and new-born till the 40th day prayers and of apocryphal prayers for an easy birth in South Slavonic manuscripts (XIV-XVII century) in comparison with Byzantine sources. The more archaic variants of prayers for the after birth period stand out, compared with the widespread later scheme, including texts about the old woman-midwife. The medieval Glagolhic and Cyrillic repertoire of prayers for an easy birth is based on one and the same evocative formula, added with instructions, dialogues, biblical quotations or names with sacred meaning. Regardless of the similarity of the texts, we can see the dynamics of their use and their functioning on the dictated by ritual border between written and oral, a border, in which the written is constantly activated by the oral, and the oral is never fully authentic.