Job Offer while Pregnant

I need some advice: I feel conflicted. I'm currently 14 weeks pregnant and was laid off two weeks ago. So I started applying for jobs immediately. I went to an interview and left feeling I would be doing the company a disadvantage working there due to my pregnancy. The company wants someone who will be with the company long enough to retire with them. If I was not pregnant, that would be perfect. I got a job offer making decent money but the truth is I don't feel right taking the job knowing I'm planning to be a SAHM once the baby arrives. I feel I'm being dishonest with the company and they'll just have to replace me after six months anyway. The position seems great and ideal for me but being I'm constantly tired, have been having bad headaches and will have to attend doctor appointments throughout my pregnancy, I feel I'm cheating the company by not being honest with them about my pregnancy or my plans. Please give me some advice. I appreciate all feedback.