Is pooping less common in formula-fed babies?

My 10 week old has been taking breastmilk since the beginning and we just started giving her formula last night (a bottle of 2 oz bm, 2oz formula). And we've been doing the same thing since and she's taking it well so far. Usually every diaper I changed would be dirty when I just gave her breastmilk, but she hasn't had one in 12 hours. Does formula make them poop less? Is this normal? I'm using Enfamil gentlease, if that makes a difference.