When do you think the first trimester ends?

[escher]

I've heard 12 weeks, 13 weeks, 13.5 weeks, and 14 weeks. What do you believe? Why?

[Gemini13]

Most of the stuff I've read says 13 weeks, although often the author will say that it's pretty arbitrary.

[Kedrosami]

Here is my slightly OCD opinion: 1st trimester ends at 14 weeks, 4 days.

Here's why: Because we assume that all women have consistent 28-day cycles and we ALL ovulate on day 14 exactly (we don't) when determining EDD we count 40 weeks from our LMP, not from conception, so those first 2 weeks you are not actually pregnant yet. I don't think those 2 weeks should count towards any pregnancy milestones because it makes you seem farther along than you actually are, which I think is what leads to so much frustration and impatience towards the end--especially since roughly half of us will go past 40 weeks anyway!

But assuming your EDD should fall *exactly* on 40 weeks and that's a reliable predictor of when the baby's due (it's not) you are only actually pregnant for 38 weeks.

1/3 of 38 is 12.67 (so let's say 12 weeks, 4 days) then don't forget to add those bogus 2 weeks from the beginning back, which gives you 14 weeks, 4 days.

By the same math, the second trimester ends at 27 weeks, 2 days. And the half-way point is 21 weeks, NOT 20 weeks...unless you have your baby at 38 weeks, then yeah. (But if you end up going to 42 weeks, like many women do, you're not half-way until 22 weeks.)

Hope that made sense and was not too nit-picky. LOL! I just think it's important to keep things in perspective since the numbers can become overly important in our minds. I like to keep track of how far I've come and how far I have to go, and I'd rather feel like I'm "early" than "late" in the end, KWIM?

[bcblondie]

13.3 weeks! Because if you devide 40 weeks by 3 trimesters, you get 13.3.

It bugs me when people say 12 weeks because then when does the 3rd start? another 12 after that? Then the last tri is 16 weeks!

Or some people don't count themselves into the last tri until 40 minus 12, 28, so that makes the second tri 16 weeks. That doesn't make sense! lol. Kind of a pet peve of mine, the way people pick arbitrary numbers.

I guess some people say 12 weeks because you pass a milestone of viability. And I'm fine with that if that's a persons reasoning.

[Lisa1970]

Yeah..that is how I count it too. LOL..I guess we have OCD together.
 

Originally Posted by radicaleel 

Here is my slightly OCD opinion: 1st trimester ends at 14 weeks, 4 days.

Here's why: Because we assume that all women have consistent 28-day cycles and we ALL ovulate on day 14 exactly (we don't) when determining EDD we count 40 weeks from our LMP, not from conception, so those first 2 weeks you are not actually pregnant yet. I don't think those 2 weeks should count towards any pregnancy milestones because it makes you seem farther along than you actually are, which I think is what leads to so much frustration and impatience towards the end--especially since roughly half of us will go past 40 weeks anyway!

But assuming your EDD should fall *exactly* on 40 weeks and that's a reliable predictor of when the baby's due (it's not) you are only actually pregnant for 38 weeks.

1/3 of 38 is 12.67 (so let's say 12 weeks, 4 days) then don't forget to add those bogus 2 weeks from the beginning back, which gives you 14 weeks, 4 days.

By the same math, the second trimester ends at 27 weeks, 2 days. And the half-way point is 21 weeks, NOT 20 weeks...unless you have your baby at 38 weeks, then yeah. (But if you end up going to 42 weeks, like many women do, you're not half-way until 22 weeks.)

Hope that made sense and was not too nit-picky. LOL! I just think it's important to keep things in perspective since the numbers can become overly important in our minds. I like to keep track of how far I've come and how far I have to go, and I'd rather feel like I'm "early" than "late" in the end, KWIM?