Heart Rate Abnormality

Hi mommies! I was just curious, for those of you who have a doppler at home, have you ever heard an arrhythmia? I was listening the other night and he was skipping random beats. I had caffeine for the first time all pregnancy and was wondering if they were related? I asked my doc and he said no big deal....it's normal to have intermittent arrhythmias. I'm not worried, just curious. I'm a labor and deliver nurse, but everything in the pregnancy stage is uncharted waters! Lol. I only know how to bring them into the world, not grow them! Lol. Should I avoid caffeine for the rest of the pregnancy? Does that mean he'll have problems after birth? Hmm.