that you shouldn't perm your hair while pregnant and many of us do not. In fact, its typical for black women to braid and/or weave or hotcomb while pregnant...ask around.
You said it was an old wives tale not to perm & that is not true. All my friends & family that have perms were specifically told not to continue that process until after pregnancy by their obstetrician. Some were advised to wait until they stopped breastfeeding also.

The fact that you are not aware, does not make it unknown medical advise. It just means that you are uninformed..as are many people about various health issues that sometimes would seem to be common knowledge. The reason they keep giving public announcements about the cat litter thing is because plenty of people DON'T know.

Are you black?