Wiki weeks and trimesters

[akaeb]

What weeks officially make up the 1st, 2nd, and 3rd trimester? I had found that the 1st trimester was less than 14 weeks. The 2nd trimester was 14-28 weeks and the 3rd trimester is 28-delivery. But I also have seen 1st trimester as less than 12 or 13 weeks.

Thanks!

 

[mitchellde]

For coding purposes this is defined for you in the code book at the beginning of the O chapter.