M.K.
I've been on the employer side: I hired someone to be a co-worker who did NOT tell us she was pregnant. I thought she was sneaky and I never fully trusted her 100%.
Even so, I would STILL advise you to not disclose your pregnancy, unless you have a personal, ethical need to do so. As an employer, it is extremely easy to find a reason any particular applicant is "not suitable for the position" for business reasons. Unless you are applying for a position for which you have extremely unique qualifications (i.e. there is almost NO ONE out there with your experience), it will be easy for them to legally document why you were not suitable, regardless of your pregnancy. It will be almost impossible to prove discrimination.
However, be aware that many companies have maternity leave policies that require 12 months of service. Hence, you may not be eligible for maternity leave. And I don't remember the FMLA policies (i.e., if you are eligible for FMLA leave prior to 12 months service). You'll need to look into this, so that you don't end-up without any time off.
As for my co-worker who deceived us...she was given 100% maternity leave benefits. However, this was many years ago when the economy was phenomenal (before the internet stock crash of 2000) and companies were making money hand-over-foot. I don't know what would happen in today's economy.
Best of luck to you!