Coffee isn't bad in moderation. Caffeine is a stimulant and a diuretic. Because caffeine is a stimulant, it increases your blood pressure and heart rate, both of which are not recommended during pregnancy. Caffeine also increases the frequency of urination. This causes reduction in your body fluid levels and can lead to dehydration.
It crosses the placenta to your baby. Although you may be able to handle the amounts of caffeine you feed your body, your baby cannot. Your baby’s metabolism is still maturing and cannot fully metabolize the caffeine. Any amount of caffeine can also cause changes in your baby’s sleep pattern or normal movement pattern in the later stages of pregnancy.

Its ok as long as you don't have over 200mg of caffeine a day.

I switched to half caffeinated, but honestly I drank one cup of coffee every morning with my daughter & she's perfectly fine. I can't give my coffee up!