The likelihood that the org will actually have any pregnant transwomen is pretty slim.
And I would think that in that situation there would be loads of things to consider and HR would be involved and supporting 1-1.
The approach should be to discuss using the largest by far group and in the most clear language (pregnant women).
And say additionally. If you manage someone pregnant who does not identify as a woman, get in touch with HR. As there are additional considerations, and as a company we want to support individually. We also understand that as a manager you might welcome additional guidance and advice.
Boom!
Done.
In this case they have indicated that the word woman when it comes to pregnancy is verboten. And they fail to take into account that additional support will be important if a person who identifies as trans is pregnant.
So it's rubbish for pregnant trans employees AND for women as they are being advised that the word that has always been used for their sex is in some way offensive.
The more I read and see the more I realise that this stuff has nothing to do with helping transpeople. And it's simply about disconnecting the standard words for (almost always) female people from the biological functions (that are the reason for the global and historical oppression we faced and continue to face).