When does a 2nd trimester offically begin?

[Kat05]

I was told from the ultrasound technician that week 12 is officially the beginning of 2nd trimester.

I've always thought week 13 was the starting of 2nd trimester. I guess I was wrong? It would be a great relief -- I really can't wait till 2nd trimester!

Title correction: officially**

 

[starsunshine]

I thought it was at 13 weeks but I don't really know

 

[misspriss]

How? Developmentally? 12 weeks. Gestation? 13w3d (1/3 of 40). Conception? 14w5d (38 weeks/3)

US/UK? In the US I think we go by the 12 week/developmental one, in the UK it's 13 more like the actual 1/3 of 40 weeks?

From the sticky in the pregnancy club:

First Trimester
US & Canada: Conception > 12 weeks
UK: Conception > 13 weeks


Second Trimester
US & Canada: 13 > 28 weeks
UK: 14 > 26 weeks


Third Trimester
US & Canada: 28 weeks > Birth
UK: 27 weeks > Birth


In the interests of website standards, BabyandBump.com starts pregnancy from the first missed period and splits 40 weeks of pregnancy into 3 equal sections:

First Trimester Forum: Conception > 13 weeks
Second Trimester Forum: 14 > 26 weeks
Third Trimester Forum: 27 weeks > Birth

Useful calculator: https://www.baby2see.com/trimester_calculator.html#trimesters_explained

 

[Inoue]

Im moving over at 14 weeks. Think from 13 weeks is normal. Its personal preference really, if you feel your ready to go over to 2nd tri and can relate to the posts then move over . Xx

 

[MeaganMackenz]

I think it's 12, at 12 weeks I'd move. In my opinion

 

[Catiren]

well since trimester means 3 months total, and 1 month is equivalent to 4 weeks, 3 x 4(weeks) = 12 so i'd say by the end of 12 weeks you've completed your first trimester (3 months).

 

[Radiance]

It's different everywhere, normally ranging from 12-14 weeks. It's always been 12 weeks where I've lived though.

 

[Selaphyna]

anywhere from 12-14 weeks

I personally think 13 weeks, but that's me

 

[btabitha]

If you go by first date of last period then it would be 14 weeks, if you go by date of conception would be 12 weeks.

 

[kissesandhugs]

1 month doesn't always mean 4 weeks so I wouldn't go by that necessarily but I know in my area 12 weeks is considered 2nd tri. I'll probably move over around 12 weeks bc it comes to a point where you can't really relate to the posts anymore!

 

[ajarvis]

Just move over somewhere between 12 and 14 weeks. Whenever it feels right to you to move over. Calendar I have says December 20th will be 2nd Trimester. Which will put me at 12 weeks. But depends on where you feel more comfortable and can relate more I think.