Go for it. You dont have to tell your boss you are pregnant until 15 weeks before you would be taking mat leave eg 20 wks +.
I wouldnt mention it until after contract signed if you do get it. I went for an interview at 12 wks pg this time and got the job. I already knew the manager and only told her a week or 2 before I started and she didnt mind. It was for a casual position eg as & when hrs so I thought that was maybe why it wasnt an issue.
Next thing I know im being offered a 6mth contract by head office with much better pay, guaranteed hrs etc I had to turn it down as I was due in 4mths and couldnt fulfil it - and they got back to me and offered me that I could work up until I wanted to go on mat leave. Now they have extended my contract by 1 year to cover maternity leave (unpaid unfortunatly), this means I can apply for internal posts, & build up sick, holiday & mat rights if I do get another job in the company next year
They also put me through loads of training courses and gave days off for MW app's without fuss.
I really cant fault them. They have been brill considering they didnt know I was 3 mths pg when applied. Only thing is its social services/NHS I work for so I suppose they are maybe at the better end of the scale for covering themselves with womens rights etc.
Def go for it. Not all employers discriminate, some may even say you in a good position being pg as they are too scared to get rid incase you sue and so bend over backwards for you! Dont feel bad about being pg!!!! Your OH is free to apply for new jobs and he having a baby too, just because you are carrying it shouldnt mean your whole life is on hold for 9 months - your still a person with rights!!!