Coffee wouldnt harm the baby,esp if you dont drink it alot.
As long as its not a lot every day you can drink coffee. It's the same as anything have it in moderation, apart from the foods that your doctor has said aren't good at all during pregnancy.
I dont think youre meant to drink cafinated coffee but im not sure as i dont like it. either way 1 drink wont harm your baby so i wouldnt worry. xx