"Just don't name it Ethel."
Announcing a pregnancy is not, contrary to popular belief, the same thing as asking for a crowd-sourced baby name. Do you have strong feelings about certain trends in natal nomenclature? Do you have a boy and a girl name all picked out for your imaginary children? That's nice. But you're not allowed to hoard names, or ask people to avoid the ones you don't like. You are encouraged, however, to wait until a name is shared, even if it's been weeks since the kid was born, and then, on hearing the news, smile and say, "How perfect!"