Gestational age vs. conceptional age...?

Question

they say that when you are 9 weeks you're baby is actually 7, since gestationally *since lmp* the pregnancy is 9 weeks but based on the actual time of conception it is about 2 weeks after lmp.

is that right? like, am i understanding that right? LOL

now why is this? is it something to do with how long it takes the baby to implant or is it just based on ovulation...

and then if its based on ovulation that would mean that its not a set 2 weeks and a woman could have conceived 5 days after lmp and therefore the pregnancy would be gestational age-11days=conceptional age.

i can't figure out how to search for this on google, obviously, because i can't figure out how to word the question right to get the results i want...so sorry if its a bit confusing. its confusing for google too.

Answer 1

Ok, If her cycle is 28 days

Count first day of bleeding as day 1

Ovulation is day 14

So when she finds out that she is pregnant, she is already 4 weeks

But the baby has only been there 2 weeks

Hope that helps  

Answer 2

Here goes: Think of a month as being 4 weeks. Normally, women ovulate 2 weeks after the first day of their period. Because it was impossible for the doctor to know the exact date you/your friend conceived, they go by the first day of your last period.

Now, think of the first day of your last period as being the first of the month. Technically, you probably didn't get pregnant until about two weeks into the month, but since the first day of your last period was the first of the month, that is when the doctor is starting your pregnancy calendar of a total of 40 weeks.

Still with me?

So, at the end of the month, the doctor will say you are 4 weeks pregnant (because your period starting the beginning of the month) but because most women ovulate two weeks later, you didn't actually conceive until two weeks ago. At the end of the month the doctor charts your pregnancy at 4 weeks, even though the fetus is about 2 weeks.

Hope this helps. :)

Answer 3

You got it right the 1st time.  Gestational age is counted from the first day of your lmp.  Conceptional age is when the sperm actually fertilized the egg.  Meaning ovulation which happens approx 14days after the first day of lmp.  Your friend is wrong to think that guy A is the father, there was not egg to ovulate.  She needs to count back to determine who she was with 22 weeks ago.

Answer 4

You're right, gestational age is based on LMP, conceptional age based on the day of conception, which most women don't know the exact date.

If your friend had s*x with two different men in a week or two, then it is WAY too close to call and either one could be the father. She needs a DNA test after birth - it is the morally responsible thing to do, for the sake of this innocent child and the two men involved. Paternity is nothing she should be playing the odds game with.

Answer 5

It is based on the LMP for reasons you have basically already said. Most women don't really know when they ovulate, because everyone has a different cycle. It is a whole lot easier to base the gestational age on a LMP a date that you should easily remember, than trying to think back to the days that you had s*x, and when you could have possibly ovulated. Also it is based on a 28 day cycle, which some women do have, but most actually don't.