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Discussion Starter · #1 ·
Hi everyone,
We got a BFP on Sunday morning and are so excited!!! I still can't believe it and need to decide on a midwife

Anyway...I have a seemingly silly question. Why is it that I would be considered 4 weeks pregnant if I conceived 2 weeks ago? Shouldn't I be considered 2 weeks pregnant instead? I understand that this calculation is based on the first day of my last period, but it doesn't make sense to me

Regardless, it's great to be further along even if I don't understand why! Maybe I just need to accept it

Any insight?
Thanks so much,
Rebecca
 

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This really baffled me too when I first found out. Because your weeks pregnant is calculated based on the first day of your last period, you haven't really been pregnant that number of weeks. So when you are said to be 4 weeks pregnant, you have only actually been pregnant for 2 weeks (if you have a 28 day cycle). I think they do it this way because not everyone has the same number of days in their cycles, and so date of conception is not as definite as first day of last period. The "nine months" thing is not really accurate; pregnancy lasts (around) 40 weeks, or ten lunar months (28 days each), starting from the first day of your last period. It is very confusing.

I have a great book "The Natural Pregnancy Book" that explains all this, and, uses REAL pregnancy time (i.e., starting from actual conception, not from your period) to explain the various stages of the baby in your womb. So when it tells what's going on at 6 weeks, it really means 6 weeks from conception, so you can get a picture of what's really going on.
 

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Isn't it annoying?

It's bothering me especially this time, because I was charting so I know my ovulation date. My cycles were really long before I concieved so my last period was 4 weeks before conception. That extra 2 weeks really means nothing at all in my case.
 

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Quote:

Originally Posted by blueviolet
They do it that way because OBs can't believe that any woman could possibly know her date of conception.

Actually, they do it that way because the vast majority of women really don't know their date of conception. Most docs will just ask your LMP, but if you have particularly long cycles, they should be receptive to changing your EDD based on that. It's not super-accurate, but better than nothing.

It's really quite simple. Pregnancy is considered to last 266 days after conception. Or 280 days after LMP for a 28 day cycle. It's exactly the same thing - you're counting to the same day - it's just a different starting point. You're really no further along in your pregnancy if you count from LMP, because you still have to make it to the same finish line.
Since full term pregnancy would be anything lasting from 37 weeks to 42 weeks and beyond, minor cycle variations that most women experience are insignificant.

But, if you know when you conceived and it was not very close to day 14 of your cycle, insist that your doctor adjust your EDD accordingly so that you're not induced early because the doc mistakenly thinks you're later than you are.

Modern medicine has to accomodate everyone, not just those that are super-aware of their bodies.
 

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Quote:

Originally Posted by chelseamorning15
Hi everyone,
We got a BFP on Sunday morning and are so excited!!! I still can't believe it and need to decide on a midwife

Anyway...I have a seemingly silly question. Why is it that I would be considered 4 weeks pregnant if I conceived 2 weeks ago? Shouldn't I be considered 2 weeks pregnant instead? I understand that this calculation is based on the first day of my last period, but it doesn't make sense to me

Regardless, it's great to be further along even if I don't understand why! Maybe I just need to accept it

Any insight?
Thanks so much,
Rebecca


Congratulations! Here's an answer to your question. They calculate gestational age based on the date of your last monthly period (LMP), so that literally, the moment the sperm meets the egg, the baby is "officially" two weeks old.


The reasons why they do this are fairly commonsensical (sort of):

1. Not all women know precisely on what day they had intercourse.
2. Not all women know precisely on what day they ovulated.
3. Not all women know precisely on what day sperm met egg.

Okay, now even assuming the ideal case, that a woman DOES know all these things (e.g., that she ovulated on the 14th, that she had sex on the 14th also and on NO OTHER DAY that month at all), here's one thing she and no one else but maybe the embryo and God know, and that's what day the fertilized embryo implanted.

Surprisingly, that can take as many as six days AFTER fertilization in the fallopian tubes. It's not until the embie implants that it starts constructing a placenta for itself and making human chorionic gonadotropins (HcG) -- the chemical detected in the urine pregnancy test.

Soooo, the embryo could have implanted right then and there on the 14th...or nearly a week later on the 20th. The clock really *really* starts ticking from when the embryo implants and starts making itself a placenta. All in all, given those factors, it's easier to go by the woman's LMP. It's also the reason for the early transvaginal ultrasounds, because babies develop nearly uniformly for the first two trimesters. In other words, if they are at X length, it's easy to see that they are X number of weeks old, if that makes any sense.

Oh, big thing!!! I don't know what you want to do regarding prenatal testing, but PLEASE, PLEASE, PLEASE make sure you have as absolutely accurate a gestational age as possible BEFORE you do one of the prenatal tests known as the "AFP Test" or sometimes the "triple screen." This test tests the amount of maternal alphafetoproteins in your blood. The AFP rises at a predictable steady rate relative to gestational age unless something is wrong. Too much AFP indicates a strong likelihood of there being a neural tube defect like spina bifida; too litte indicates a strong likelihood of Down syndrome or other chromosomal abnormality.

The thing is, if the test is off by even a week, it will give back a false result -- and to hear that your baby MIGHT have Down or MIGHT have spina bifida is about the very last thing you want to hear when you're pregnant.

Trust me.

For instance, in my case, my doctor -- may he come back as one of his own patients -- would NOT listen to when I told him the baby was conceived. (I kept a calendar and I knew it had to be one particular day.) He went by the date of my LMP, two weeks earlier, and wrote down on the test that she was 17 weeks old. Actually, she was 15.

Anyway, the test came out as "too low" a quantity of AFP. This meant that according to the test, there was a strong possibility she had Down syndrome.

It was like getting kicked in the belly. We had a level III ultrasound and they took multiple measurements (biparietal diameter, femoral length, nuchal fold, et cetera) and calculated her dates as being...surprise! Fifteen weeks old. Therefore, she was probably normal, but my happy little balloon of complacency had been completely popped and I finally requested an amniocentesis because only the amnio can tell you beyond all doubt if there are chromosomal abnormalities of that type. Even the level III ultrasounds can miss some subtle signs.

So anyhow, if your position is, "I will accept whatever God / Allah / YHWH / Kali / karma/ Hera / Fate / Life gives me no matter what," then skip the test.

If your position is somewhat different, you might want to consider skipping to the amnio if you're a "geriatric pregnancy," which most OBs define as being over thirty-five.
: I know many MDC folks may not agree with this level of intervention, and I can't say that I blame them. Your call.

I wish you well!
 

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Discussion Starter · #7 ·
thank you so much everyone!
I GREATLY appreciate the responses

Your info. really did help. I understand now that most of the calculations are based on averages.
I was charting, so I know when I o'ed, and most likely when we conceived so I'll bring all that information with me to my first midwife appointment and take it from there.
Thank you so much again!
You are all wonderful

Rebecca
 

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Hi Rebecca, this is totally OT - but I love your screen name - how did you pick it? My name is Chelsea and I was named after the Joni Mitchell song "Chelsea Morning" and it is still a song I love and have to listen to every year on my b-day...
I was just curious as I thought you would be named Chelsea too...
and congrats on your pregnancy - I am 9 weeks and still confused about the whole counting weeks thing... The book I have called "Your Pregnancy Week by Week" is really good because it states both ways of counting - each week it will say "6 weeks pregnant - gestational age 4 weeks" and etc. so it is easy to keep it all straight...and it gives you great detailed info about exactly what is happening in each week....
Good luck with your midwife hunting!
- Chelsea
 

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Discussion Starter · #9 ·
Hi Chelsea!
Thanks for writing

I chose my screen name from Joni's song...that's so cool that you're named after it!
Congrats on your pregnancy--it's wonderful to "know" other people going through the same thing. We haven't told anyone yet, so it's still our little secret

Thank you for the info. on the book! I think that I've narrowed it down to 2 different midwife practices. One actually has an office manager, so that would make life easier with insurance and appointments and stuff, but we'll see. I'm planning to send emails to them both this weekend.
Thanks again for your post,
Rebecca
 
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