Will cause you no problems. They couldn't risk having something that would adversely affect pregnant women...imagine the cost of the payouts in claims and legal fees if they did??
I think that it is not recommended and even dangerous. Its a scanner to see if you are carrying something dangerous or just the metal detector? Of its the first, do not do it. Its like passing a ct scan at the hospital: its not for pregnant women.
I know in germany they have a scanner to scan people for dangerous stuff and that if you are pregnant, you cannot go through it and you have to have a body search instead.
Thank you all for responses