When to tell boss

I told my boss at 8 weeks due to an upcoming long haul work trip I was supposed to attend. So had to tell boss to manage expectations/send a cover. If I had the choice I would wait till after first tri

I told boss at wk 9 as I would like the information to sink in and allow time to make plans to cover my role to make plans to hire temporary staff , during my confinement period.

I told my boss after my gynae check confirming the baby’s heartbeat, but told him to keep confidential from others until 1st trimester is over :)