I am pregnant and have used 5 hour energy drinks. Is that bad?

I have used the 5 hour energy drinks in very little moderation. I'm 17 weeks pregnant and have never drank a full bottle. I only use this about 2-3 times a month. What I do is take a small sip and then throw away the rest. I never get the niacin flush or jittery. It just perks me a little. I don't need it...I just use it when I am literally falling asleep at my desk at work. So I'm not ingesting all the caffeine or the vitamins. I just want to know how bad it is to even drink that little bit.