When does 2nd trimester start?

[Deleted User]

Just wondering what you consider to be the start of second trimester? I have a few different pregnancy apps and they tell me something different. My Bump app tells me second tri starts week 14, but a different app (called "I'm Expecting" by MedHelp), tells me that I'm now in the second trimester since I've hit 13 weeks today. I never actually asked my doctor what she considers to be the "official" beginning of second tri. What do you guys typically go by?

whiteroses05

I have what to expect when expecting book it says 13 weeks. I have heard mixed of things too but more so it being 12 or 13 weeks. I would say you are in second trimester. Congrats!

2redtulips

It's anywhere between 12 and 14 weeks, according to my doctor and various other sources, but I just decided for myself that it was 13 weeks.

Squiddly

I used 13 and half weeks because 40/3 is 13.33333333333...

nyg2042

I divided 40 by 3, and went with 13w3d, but I have heard anything between 12-14 weeks,

doglover31

My doc said 14 weeks but I have read various responses to this from 12-14 weeks

BkBaby118

I found this trimester calculator the other day: https://www.baby2see.com/trimester_calculator.html. I still find it a little confusing, but apparently you can calculate by development, gestation, or conception. Most places, The Bump included, say that 2nd trimester begins at 14 weeks.

voplo

According to my OB 13 is the last week of your 1st trimester. You start your 2nd on the week 14. Also the 27th week is the last of the second and the 28th week is the start of the third trimester.  I asked him time ago because I was confused by several different opinions in websites. No that it matters too much, but it is always great to know when you get into a new trimester

Edited: some wording problems. Working on my english...

katiebartton

Qfrump said:

Same as @squiddly and @nyg2042, I went with 13w3d, but then I did ANOTHER happy dance at 14 weeks.  And pretty much every day since then.  If you click "progress" in my signature and put it your own due date you can even see what % you are!

Another 13w3d here too