When it is said
In the old Roman rite a priest said these prayers at a Mass for a woman who had no child, naming her where the book leaves a blank.
A husband might pray them for his wife, or a wife for herself.
Where it comes from
No author known
A Mass for a woman with no child
The Gelasian Sacramentary is a service book of the Church of Rome. Its one surviving copy was made near Paris about AD 750, from older Roman material. Its Mass for women who have no child has seven prayers, and six of them recall a mother in the Bible. This page gives three of the seven: the second, the sixth and the seventh.
H. A. Wilson (ed.), The Gelasian Sacramentary (1894), pages 269 to 270; The Cult of Saints database, University of Oxford, E07005
A mother’s heart
Later in the same Mass the priest prays over the bread and wine for the woman. He asks God to take away her grief at having no child and to bless her to conceive, because God has set the love of children deepest of all in a mother’s heart.
H. A. Wilson (ed.), The Gelasian Sacramentary (1894), page 270
What the words mean
Who is Gregory?
The second prayer on this page asks for a child “through the prayers of Your servant Gregory” but does not say which Gregory. The book’s editor in 1894 thought it most likely meant St Gregory the Great, though he could not be quite certain.
H. A. Wilson (ed.), The Gelasian Sacramentary (1894), introduction
The Scripture in it
Later, Isaac prayed to the LORD on behalf of his wife, because she was barren. And the LORD heard his prayer, and his wife Rebekah conceived.
Bible text: Berean Standard Bible, public domain.
In Latin
Deus, qui famulum tuum Isaac pro sterilitate coniugii sui te deprecantem exaudire, et conceptum Rebeccae donare dignatus es, preces famulae tuae N. pro percipienda prole benignus exaudi; ut firmamentum spei, quod in tua misericordia posuit, ei ex percepto munere quod postulat confirmetur. Per.
Deus, qui anxietate sterilium pie respiciens, in eis fecunditatem etiam in sua desperatione mirabiliter operaris, concede propitius ut famula tua N. de percipienda sobole, quod per se non valet, servi tui Gregorii mereatur precibus obtinere. Per.
Omnipotens sempiterne Deus, qui maternum affectum nec in ipsa sacra semper virgine Maria, quae Redemptorem nostrum genuit, denegasti, concede propitius ut eiusdem Dei genitricis precibus famula tua N. esse genitrix mereatur. Per.