I think you will find that the relevant words are
… et in Iesum Christum, Filium Eius unicum, Dominum nostrum, qui conceptus est de Spiritu Sancto, natus ex Maria Virgine,
So “conceptus de” holy Spirit, and “natus ex” the holy Virgin.
To conceive is something like “receiving pregnancy”, and that is exactly what happend. The holy Virgin got pregnant by the holy Spirit, as you can read in Luke 1:31 and Luke 1:35. 31 is most interesting, as it clearly states (I quote from the USCCB Bible I found online)
Behold, you will conceive in your womb and bear a son, and you shall name him Jesus.
So that is the conceiving part, the holy Spirit was responsible for “putting Jesus in the womb of Mary”. In a biological birth, that would be what the father does, in this case it is a metaphysical happening, but nevertheless, what the holy Spirit does here, would hardly be called “maternity”.
Of the holy Virgin not much about the conceiving part is said in your text. What is said, is that Jesus was born of her, natus ex. Now that is what you would associate with “maternity”.
I can hardly believe anyone ever has thought that the holy Spirit and the holy Virgin had somehow a similar part in this. As Luke states
Therefore the child to be born will be called holy, the Son of God
This relates to the holy Spirit (yes, the third Person in the Trinity, God). The part of the holy Virgin is why we call her Θεοτόκος, theotokos, the God-baring, or the mother of God. Jesus got the flesh from the holy Virgin, the human body was formed like all humans after Adam and Eve are formed, in the womb of their mother, being fed by their mother so they can grow and be born.