Hi
I haven't been in this position myself but have chaired many interviews on behalf of the company I work for. Employers should not discriminate on the basis of pregnancy and should only discount a pregnant applicant on the basis that their skills and experience are not the most suitable for the post. The best advice I can give is to complete application forms as you usually would and, if invited to interview, be honest about your pregnancy, the jobs you are able to do and the hours you intend to work on your return. Working mums are a positive asset too.
Good Luck x