Should you disclose your pregnancy in an Interview?????

Well, I am confused if or not one should disclose pregnancy news in an interview. Even though ethically I feel like its something very important and one should not hide but it has always been seen that it impacts the interviewers decision. Legally an employer is not supposed to discriminate on the basis of whether or not a lady is pregnant but unfortunately the trend has been that it does come to the hiring authorities mind as in if or not hire someone who may take maternity leave soon. But then, that can give a wrong impression just in case you end up getting that offer and end up accepting the same. Very critical situation!!!!!

Also, what would you do if you would not disclose in the begining then when do you think it should be disclosed and how????

Please advise..........