I did not consume any caffeine when I was pregnant with my first child. I cut out all caffeinated coffee, tea, and pop for the entire duration of my pregnancy. I continued a caffeine-free diet after my pregnancy too while I was breastfeeding. Everyone, including my doctor told me that it was best not to consume any caffeine because it could have negative consequences for the baby. So I listened... for the first baby...
This past pregnancy (my second child), I ignored that advice. I drank coffee almost every morning of my pregnancy. I did not consume a lot, maybe 2-4 cups per day. I was a little nervous about doing it but coffee works like an antidepressant for me. I really feel that it helps me be a better, nicer person (and mother!). I am sure I am not the only one that agrees with that statement! As the time grew nearer for my baby to be born, I started to feel paranoid that my baby was not going to sleep because I had consumed too much caffeine. Once he was born, I continued to ignore that fear and I drink my morning cup of coffee.
Funny thing is that both of my babies had about the same sleep schedule and similar behaviors. They both required feedings every 2-3 hours around the clock for the first month, into the second month. I believe my second baby (where I consumed caffeine) slept longer earlier than my first baby. He currently sleeps 6-8 hours in a row starting when he turned two months old. He occasionally sleeps less, but the sleep schedule fluctuated a little with baby #1 too. I reread my old blog post, Sleepy Mommy & Daddy Pictures, to find that my first baby started sleeping 8 hours in a row at 10 weeks old. Both babies were/are not colicky. They cry when they need a diaper change and when they are hungry. That is pretty much it.
Therefore, based on my experience, drinking caffeine while pregnant and breastfeeding has no effect on the baby. I am not a doctor, nor am I promoting caffeine use during pregnancy! I am just stating my personal experience for those of you who are also feeling guilty about consuming caffeine during pregnancy and breastfeeding.
Best of luck to all you mamas! =)