What is the basis for saying Mary is not the mother of God from a trinitarian perspective?

Note: I scoped this question to trinitarians because Christ could be rejected as God and thus it wouldn’t be relevant to non-trinitarians. I was recently inspired by user @Anne to ask this, as she said that Mary was not the mother of God, but didn’t want to discuss in the comments. Now this was a rather odd claim to hear. Mary conceived and gave birth to Jesus, who is God. That’s true on trinitarian belief. Now as far as I’m aware, conceiving and giving birth to someone makes you a mother. So what’s the basis for rejecting Mary as the mother of God? ---------- Opposite question: https://christianity.stackexchange.com/questions/54531/what-is-the-biblical-basis-for-the-belief-that-mary-is-the-mother-of-god