20ml of coffee once a day is okay according to doctor friends. But my OB banned me completely bec I have hypertension. She also said that caffeine usually results to smaller babies. But if your OB says it's okay, then you're good. Just don't have too much.
if your ob is okay with it, i don't see the cause for worry. but if it worries you, you can.have it every other day or lesser.