What brand of prenatals works best for your body?

I'm not sure if I am the only person that gets constipated while taking any type of vitamins. I have taken two different brands of prenatals in the past 6mo. One was perfect (will be buying that again) and the other, totally got me constipated. Looking for suggestions. What brand works best for you? And do ya'll have the same issue as me? I can't be the only weird one here.