Will it be frowned upon

First of all, they can't legally discriminate against you for being pregnant. So if they retaliated or took the job away or something, you could sue them or take them to court or something.
That being said, it's hard to predict their response, not knowing your relationship with them or the type of company they are or how they treat their employees, etc. I've had great jobs where they hired me knowing I was pregnant and worked really well with me on managing OB appointments and figuring out maternity leave and all that. I've also had crappier jobs where I felt like they started treating me worse after finding out I was pregnant. But there was no proof of that unfortunately.
Anyway, to answer your question, I think they will probably understand the situation and will be okay with it, especially if you're planning on returning to work after maternity leave. I think the main disappointment would be if they thought you were quitting after having the baby. I don't think pregnancy is too concerning in general.

i guess it would depend on how you think they will take it? do you know them enough to be able to guess?

legally they cannot discriminate against you for being pregnant- however i have know employers to go about getting rid of someone once they find out by saying "they're just not meeting the needs of the role".

i interviewed for a position and knew i was pregnant. i've just started this week at 16 weeks and will tell them this week just to be nice. Legally you don't have to tell them until your 25or 26 weeks (i don't remember which.

also they can't really moan if you're only planning to take of 2-4weeks when you're entitled to 52 weeks.

go with you gut & congratulations❤️❤️

Sorry I typed more than I thought I would. 😅 But I also wanted to mention, a lot of people wait to announce pregnancy until they're at least 10 weeks along (that's what I did) in case of miscarriages. So I don't think it's unreasonable to wait to tell them until you're ready either. And you're not technically required to tell them anything, other than HR would at least need to know in order to work out maternity leave. But I told my bosses when I was pregnant in order to keep them in the know in case I was getting sick at work and to help coordinate appointments and stuff.
Sorry that was a lot 😅 But I hope it helps!

Sign the contract first and tell them like two weeks later

Thank you Ladies this is really helpful. My new Line manager just had a baby and has been very flexible with his working hours and they really want me for the role so I am hoping they won't take it badly and be understanding.

My job is predominantly home based as I am a Project manager so in terms of my work schedule it is already pretty flexible in terms of appointments.

Thank you for all the info on disclosure it's useful to hear it from actual people and not google.

I think I will sign the contract and wait till about 12 weeks to disclose.