Going for new job but just learnt I'm pregnant

[ChinaSurprise]

I recently went for a big promotion at work to a different department. I didn't get it but was told that a similar position was coming up soon and that, off the record, I was almost certain to get it.
The new position was advertised and I applied. In the last week I've learnt I've got an interview, and that I'm pregnant!
Now I don't know what to do. I really want the job and I know I'll be good at it. My husband will be a stay at home dad so I'm planning to only take two months maternity leave. Assuming I get the job I'd be likely to be in at least my 12th week before I start.
Assuming I get the job, when should I tell my new boss? Should I tell him if/ when I'm offered the job or wait a bit longer? I know I've got until the 25th week - but I'll ne showing way before then. My legal rights to SMP etc should be fine as I'd be moving within the company but I'm worried about annoying people I've only just met and being pre-judged by them and I'd be on probation for three months in the new position, which is also worrying. Finally, the new job would involve taking part in a sport my doctor has advised my against while pregnant - it's not a compulsory part of the job, but it will raise eyebrows if I don't give a reasonable explanation as to why I don't want to do it.
Help!

China don't let your pregnancy affect any decision you might make about this job. It's so common for women to feel apologetic about getting pregnant and also to worry that people will judge them. You are just as capable of being an asset to the team, and particularly if you only intend to take a very short period of maternity leave, the disruption should be minimal. (Although please bear in mind that a large proportion of women change their minds about the length of their maternity leave after they have had the baby).

I would not tell your new manager until after you have been offered the job. You may want to wait until you are 12 weeks as many people do anyway. Although you will have to say earlier than that if you will be expected to take part in this sport before that time. Your employer is obliged to do a Health and Safety Risk Assessment for you to identify whether there are any risks associated with your job which may affect your pregnancy, and obviously this sport being unsuitable should be identified as one of them - even if not you will easily be able to get a doctor's note for it.

Your probationary period in the new job shouldn't worry you. This period is about demonstrating your ability to do the job effectively, which has not changed. If you find extreme tiredness or morning sickness affecting you, be sure to make your boss aware quickly, that way if issues are raised during this probationary period which may have been affected by your pregnancy you should be fine.
HTH

Hi flowery
Thanks for the encouragement. It's nice to hear supportive words.
I do take your point about wanting to have longer maternity leave - in an ideal world I wouldn't want to return to work for several years. Unfortunately though, I'm the main breadwinner in our household - I earn about three times what my husband does, so it's just not possible to swap roles! Also, he works from home part-time already and as a freelancer can be completely flexible about his hours, so this way round just makes a lot more sense. Plus, I know he'll be brilliant, he's going to be such a great dad.
Anyway, I'm getting off topic. I think your advice is good and you're right that I shouldn't be feeling apologetic. I didn't know the health and safety assessment was obligatory, so this should help. I guess if they're a decent boss they'll be able to keep it to themselves for a while anyway.
Who knows, I might not even get the job!
Thanks for taking the time to write - I really appreciate it.
China