# weeks and trimesters



## akaeb (Jul 21, 2017)

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!


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## mitchellde (Jul 21, 2017)

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


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