With my first son i stated to get full and leak at @20weeks with this second boy i didnt leak at all and didnt get full but im breastfeeding with no problem.
Ive had some degree of a milk supply for 6 years since I had my first daughter. I am always able to squeeze a little out. When Im pregnant it gets worse and I tend to leak.
With this one I had a noticable leakage episode at around 9 weeks.
Depends on the woman I think. With me, I never had my boobs leak. Even after my daughter was born! I guess I am one of those that just can't get milk in. Who knows!
It's rare, but they can start leaking early in your first trimester. Mine started at 21 weeks.
idk but.my started to around 25wks