When does 3rd trimester start?

[Pepper123123]

I'm 27 weeks. I have two apps, one tells me I've been in my 3rd trimester since last week, one tells me I'm still in my 2nd. Some websites say 3rd trimester begins at 27 weeks, some say 28.

Very confusing!

I know what you mean. I have three pregnancy apps and they all say different things for the second and third trimesters. Very frustrating!

2nd starts on your 13th week
3rd starts on your 29th week

So that's four different weeks of pregnancy I've heard now 😄

I suppose the NHS website would be most reliable. That says 28 weeks, so I think I'll count it from then.

Rather than thinking in weeks, I looked at it in months. Months 1-3 are first trimester, 4-6 sept second, and 7-9 are 3rd. This means 3rd starts around 27.5 weeks. But it’s just a label, doesn’t actually matter.

Most things I read said 28 weeks.
Doesn’t matter too much really though!

I was speaking to some who was saying " whoop I'm 36 weeks today, finally 9 months pregnant!"

I was like whaaaaat?

Apparently an app told her she was 9 month pregnant.
So if she goes 2 weeks overdue then you're 10.5 months pregnant?
Nay.

I'd go by NHS website and 28 weeks.

I have an app that says 27 weeks too, but I go by 28 in reality as that is what the NHS goes by, so that seems the most relevant one as they're providing my care. It's pretty arbitrary though (else there wouldn't be different places saying different things!) and any HCP generally ask for number of weeks pregnant anyway.