A pregnant person is a woman.
I'd question the association between mother and woman, rather than mother and birth
It’s the same with people who menstruate — not only for trans men but for post menopausal women, women who’ve had hysterectomies, or are otherwise have amenorrhea.
Particularly when that language control is transparently used for power seeking.
We don’t need to shape every utterance around outliers — that’s pathological and stifles discussion.
Normal people instinctively understand this, and “woman” and “mother” are completely understandable and useful terms, even if there are a handful of exceptions out of millions are exceptions to the strict definition.