Hmm, I've not heard that before. You might try to do a little more research on it, or speak with a naturopath or OB to see if anyone knows more about why. I can't imagine that papain (found in papaya) or bromelain (found in pineapple) could be harmful, since pregnant women eat those foods and therefore take in those enzymes regularly. I have a great product I love called Digestive Enhancement
, but that one has quite a few different enzymes in it. You might try to stick with just the papain and bromelain while pregnant. I would think that would be safest.