Smoking pot

I have read on here that there are so many women that are smoking both pot and cigarettes while TTC and while being pregnant I just don't understand why a woman would jeopardize the health of a baby while being pregnant. Now I'm not saying that I don't smoke because I do but when I find out that I am pregnant I will be stopping smoking cigarettes. I will not let anyone to smoke around me because I am not willing to put either me or my baby in any harm as far as smoking. Please tell me if I'm wrong but that is just how I feel about this.