Caffeine intake???

Samantha • Life is short. Find someone to love completely.
I've been keeping track, because I have read to keep caffeine intake under 200 milligrams a day.
But the other day, my dad told me he saw an article saying that the 200 milligram research is old and that caffeine intake should be much less!
He thought he tagged me in it on Facebook, but he didn't and now he can't find it.
Does anyone know the correct information about the amounts of caffeine that are appropriate for a pregnant woman?