2nd tri - 12 or 13 weeks?

[MiasMum]

Im finding different things on the internet. Some places say 12 weeks, others 13.
Ive got my 12 week scan next friday when ill be 12+2 and wanted to tell people then. x

 

[NurseSooz]

I always say 12 as that's when your scan is and many start telling people. I feel the scan is the passage into second trimester!

 

[xdxxtx]

In the US, 14 weeks is the standard, but I think in the UK, it is 13 weeks. I divide 40 weeks into 3 - so rounding down to 13 weeks is fair.