Two women, working in very close partnership. Basically the only people, apart from service users, in the same room all day everyday.
One is pregnant, the other on her third (and likely final) round of IVF.
The one who isn't pregnant is clearly in significant distress, but this is coming out as her being truly vile to the pregnant one, who is basically being bullied for being pregnant, a protected characteristic.
Pregnant colleague does understand how hard it must be and is trying to be tactful, but also wants to enjoy her pregnancy.
So the behaviour against the protected characteristic needs to be managed, but the other colleague is really struggling too.
TBH I think the best answer is probably that the non-pregnant woman is signed off sick, but I don't think I can suggest that.