According to this site end of week 13. But my doctor called me the first day of my 13th week (3 days ago) and told me congrats tht i was in the 2nd trimester now(:
End of 12 weeks, when you enter your 13th week
It begins at the end of your 12th week.
Okay thank you some say end of week 12 an others say 14 weeks I wasn't sure
I always thought after 12 weeks but according to this website must be 13