anyone in the UK not told their boss?

Samantha

I work part time as a cleaner only a couple hours a week at an office block and never see my boss but tonight I'm having a meeting with him and other members of staff as he is leaving and we will have a new boss but I haven't told him I'm pregnant yet, has anyone else not told their boss they are pregnant yet? And should i tell him before he leaves of wait for this new guy to take over then tell him Instead?