Conflicting info when1st trimester is over

B3Bride

I see on many websites at 12w developmentally you are out of the 1st trimester but gestationally you are out of the woods at the end of the 13th week. Which one are you or your Dr. using?

flippy1234

I thought it was after the end of the 12th week. So when you are 13 weeks you are in 2nd tri....

ReneeDerek04

My Dr. considers you in your 2nd tri at the end of 12 weeks, so as soon as you START the 13th week you're in your second tri.

SaraF30

flippy1234:

I thought it was after the end of the 12th week. So when you are 13 weeks you are in 2nd tri....

That's what I think too.

aldyn

Maybe I'm too analytical - but this doesn't seem like rocket science to me -

Normal gestation = 40 weeks

I trimester implies 3 periods of time.  So, each trimester = 40/3 = 13 1/3 weeks.

You begin your second trimester 1/3 of the way through your 13th week.

SparkleK

Don't the nest gods go by 13 weeks, 3 days?

In one of my baby books, I read that not all trimesters are created equally and the first trimester actually ends and the end of the 14th week.  I haven't read that anywhere else, though, and DH and I have probably read 6 books between the 2 of us.

Mrs.Albie

I consider 13w 3d as end of the 1st tri. 

JillAly

Mrs.Albie:

I consider 13w 3d as end of the 1st tri. 

Me too.  If 3 trimesters are equal, then 13w, 3d is the end of the first.

lsanpasc

I would rather go by developmental stages than crude arithmetic... so I say once you're in your 12th week, you're in the 2nd tri. But many others disagree.

mrsdan2009

My doctor says the 2nd tri starts at 12 weeks 0 days. so i'm going with that.