Job discriminatin and Pregnancy
Let me start off first by saying it is illegal for perspective employers to ask if you are pregnant or not. Of course if you're showing and do not look like you're just packing on extra weight then you have already offered that information even unintentionally. Now they also cannot deny you employment solely based on the fact that you are pregnant since this is also against discrimination laws. They can however list all the duties of the job and ask you if you can honestly perform or excel at them.
Even the most understanding of employers might not want to hire you simply because they know there is going to be a time in the not so distant future that you will be out of the office due to actual maternity leave not counting any possible complications that force you to be out of the office.
My human resources department and supervisor have been very understanding since I developed a severe medical issue called Grave's Disease during my last pregnancy. I was honest with my supervisor and called her when I had to go to the ER because something didn't feel right and they ended up forcing me to stay home due to the severity of the condition. Fast forward to present where I have a beautiful six week old baby girl and my doctor just gave me permission to go back to work after nine straight months of disability because of that condition. I ended up having surgery to correct it and then was on a modified bed rest due to what the disease did to me and the baby. She is perfectly healthy just smaller than the doctors expected. If I had been forced back to work there was a chance I could have miscarried her or had a late stage stillbirth and employers do not want that type of responsibility to make the determination if you can perform job duties based on your pre-pregnancy self.
I recommend not calling attention to the fact that you are pregnant. Instead wear looser clothing that still looks professional such as a nice blazer over a blouse. The blazer can detract from the presence of a baby bump unless you are showing extremely early. If you are given a job offer, then mention the pregnancy so the employer does not feel that you lied to them when you show up to your first day at work and you're obviously pregnant and to get that much needed health insurance for you and baby. Another reason employers tend to subconsciously shy away from hiring pregnant women is that some women do not return to work and instead prefer to stay home with the child and the employer doesn't want to hire a short term employee but a permanent one.
"The Pregnancy Discrimination Act is an amendment to Title VII of the Civil Rights Act of 1964. Discrimination on the basis of pregnancy, childbirth or related medical conditions constitutes unlawful sex discrimination under Title VII. Women affected by pregnancy or related conditions must be treated in the same manner as other applicants or employees with similar abilities or limitations. An employer cannot refuse to hire a woman because of her pregnancy related condition as long as she is able to perform the major functions of her job. An employer cannot refuse to hire her because of its prejudices against pregnant workers or the prejudices of co-workers, clients or customers." - Taken directly from the US Equal Employment Opportunity Commission website at eeoc.gov.