When does the 3rd tri begin?

kqualls5

When exactly do you enter the 3rd tri? I've read a lot of things that say 27 weeks, but The Bump says 28. 27 makes the most sense (dividing 40 weeks by 3 is 13.33, so mathematically you're two-thirds done at 26.66 weeks). But did any of you ask your OB's by any chance? (I know, this is a question I should ask mine, but I forgot to at my appt yesterday)

kyraaD

i found this chart. it's really helpful (:

SamanthAnalise

Divide the amount of weeks that you are by four. For instance: If you are seventeen weeks, you are 4 months pregnant!

DrillSergeantCat

SamanthAnalise said:

Divide the amount of weeks that you are by four. For instance: If you are seventeen weeks, you are 4 months pregnant!

There are more than 4 weeks in a month. Your math will be off if you do it this way.

redfallon

DrillSergeantCat said:

SamanthAnalise said:

Divide the amount of weeks that you are by four. For instance: If you are seventeen weeks, you are 4 months pregnant!

There are more than 4 weeks in a month. Your math will be off if you do it this way.

Yep. 52/12 = 4.333

The chart above, or others that you can find through Google, are great references.

kqualls5

redfallon said:

DrillSergeantCat said:

SamanthAnalise said:

Divide the amount of weeks that you are by four. For instance: If you are seventeen weeks, you are 4 months pregnant!

There are more than 4 weeks in a month. Your math will be off if you do it this way.

Yep. 52/12 = 4.333

The chart above, or others that you can find through Google, are great references.


This issue is they're all different lol. That's why I was just curious if anyone has asked an actual OBGYN. If you just type in to google "when does 3rd trimester begin" it says at the start of week 27. But then on a lot of apps it says 28. And the calendars don't make sense at all because they're not divided evenly at all. I'm 28 weeks now, so I'm in the 3rd tri by every calendars standard, I was just almost 27 weeks when I asked and wanted to know if I was almost to the 3rd yet. Thanks anyway though!

redfallon

@kqualls5 said:

DrillSergeantCat said:

SamanthAnalise said:

Divide the amount of weeks that you are by four. For instance: If you are seventeen weeks, you are 4 months pregnant!

There are more than 4 weeks in a month. Your math will be off if you do it this way.

Yep. 52/12 = 4.333

The chart above, or others that you can find through Google, are great references.

This issue is they're all different lol. That's why I was just curious if anyone has asked an actual OBGYN. If you just type in to google "when does 3rd trimester begin" it says at the start of week 27. But then on a lot of apps it says 28. And the calendars don't make sense at all because they're not divided evenly at all. I'm 28 weeks now, so I'm in the 3rd tri by every calendars standard, I was just almost 27 weeks when I asked and wanted to know if I was almost to the 3rd yet. Thanks anyway though!

It's probably one of those things where it's in the middle of those two weeks, like 27 and 3 days or something.

SaraSeanJ

This depends on if you think a pregnancy lasts 9 months or 40 weeks...(because 40 weeks is really more like 10 months, but ugh who wants to be pregnant that long, right?

lalala2004

SaraSeanJ said:

This depends on if you think a pregnancy lasts 9 months or 40 weeks...(because 40 weeks is really more like 10 months, but ugh who wants to be pregnant that long, right?

The only month that has 4 weeks is February. Also, the first two weeks you weren't actually pregnant.

katy0990

I have wondered the same thing. Since everything is based off of 40 weeks, it makes sense to me that at 26 weeks 4 days you would have 1/3 of the pregnancy left to go.

2-Step

There are 270 days in 40 weeks - divide by 3 and you get 93.33 days per trimester. Divided by 7 to find out the number of weeks in a trimester = 13.33 weeks. Multiply by 2 for your first two trimesters and you get 26.6 weeks, .66 weeks is 4.62 days, so after 26 weeks and 5 days you are technically in your third trimester. Maybe those apps are taking into consideration the two weeks at the beginning that you are technically not pregnant? That doesn't make much sense to me since everything else is based off of 40 weeks. Math beats an app IMO. Either way, congrats on your third tri!

ETA - I guess the first step was irrelevant, but you get the point!

soxfan9968

2-Step said:

There are 270 days in 40 weeks - divide by 3 and you get 93.33 days per trimester. Divided by 7 to find out the number of weeks in a trimester = 13.33 weeks. Multiply by 2 for your first two trimesters and you get 26.6 weeks, .66 weeks is 4.62 days, so after 26 weeks and 5 days you are technically in your third trimester. Maybe those apps are taking into consideration the two weeks at the beginning that you are technically not pregnant? That doesn't make much sense to me since everything else is based off of 40 weeks. Math beats an app IMO. Either way, congrats on your third tri!

ETA - I guess the first step was irrelevant, but you get the point!

The 40 week count also includes the first two weeks when you're technically not pregnant.

skruhmin

So if you carry the one, then subtract the 5, then the swallow flies east at midnight, I will give birth to a dragon, right?  But is that only if the nub is pointing down?  MAN I'M SO CONFUSED!!!!

ecwk

skruhmin said:

So if you carry the one, then subtract the 5, then the swallow flies east at midnight, I will give birth to a dragon, right?  But is that only if the nub is pointing down?  MAN I'M SO CONFUSED!!!!

No, no, no @skruhmin! We've been though this! The swallow must fly west and *only* during a full moon. The rest of it you got right  

skruhmin

ecwk said:

skruhmin said:

So if you carry the one, then subtract the 5, then the swallow flies east at midnight, I will give birth to a dragon, right?  But is that only if the nub is pointing down?  MAN I'M SO CONFUSED!!!!

No, no, no @skruhmin! We've been though this! The swallow must fly west and *only* during a full moon. The rest of it you got right  

lionstigersbears

So I don't have an answer but I got an explanation from my midwife about 1st vs. 2nd. She said medical textbooks will consistently say 12 weeks is the beginning of 2nd trimester. Apparently variations seem to be related to ultrasound reports and designations outside the medical field. Perhaps look into a medical text about 3rd tri? The practice I go to doesn't define in but explains it this way so...there's that.