Pregnancy one didn't tell anyone for years - mc
Pregnancy 2 told immediate family around 6 weeks then mc
Pregnancy 3 didn't tell anyone until 14 weeks and had scan, this is when we told immediate family, didn't tell anyone else until I was about 5.5 months except for I told my immediate boss in confidence. She'd had mcs too and was incredibly supportive and understanding and had literally saved my life earlier that year when I had collapsed at work with Gynae complications (ovarian torsion which she'd also had herself and recognised the signs and got me help very quickly. It was a complicated case and if she hadn't got me help as fast as she did and pointed out certain things to the paramedics that I'd said to her before I passed out I dread to think what could have happened). By 5.5 months I was just starting to show so that prompted telling people, several were very surprised how far along I was.
Everyone's different. I give the impression of being an outgoing and open person but I'm actually deeply private in real life and I didn't want people knowing and kind of watching me in case things went wrong again. It was not a smooth pregnancy for a number of reasons and I was being closely monitored which I also didn't want to get into with people. Right enough when we did tell people I was given a lot of unsolicited, well meaning but potentially dangerous advice on the issues I was having.
If I had lost dd (which I almost did at various points) I wouldn't have wanted to have to tell a lot of people and keep going over what happened.
I appreciate my circumstances were somewhat unusual.
My sister had no choice as she was vomiting pretty much constantly from BEFORE she was even at peeing on a stick stage! The first time she thought it was a bad bout of noro! The point at which she found out she was pregnant she was on a fluids drip and barely conscious in a hospital bed. The next 2 she knew straight away what it was as the nausea apparently had a definite quality to it she recognised. Again each time before even missing a period she was decorating bathroom walls. She has it horrific every time.
A neighbour I knew didn't even know herself until the birth! 3rd baby, very sim lady I'd seen her at the corner shop day before the birth and she was in skinny jeans with no hint of a bump! Few days later saw her pushing said baby in pram thought she was babysitting for someone. She'd gone into Labour in the night at first thought it was something like appendicitis, baby delivered on bathroom floor by husband following instructions from 999 operator!
So yea, everyone's different. So what's right for you.