Determining how far along you are..?

Question

How do doctors determine how far along you are? When do they count from? The first day of ur last period or? I wouldn't think that they would count from ovulation because not everyone knows when they ovulate.... plz help, thanks!

Answer 1

they determine your due date by the date of your last menstrual cycle. technically its take that date...subtract 3 months and add a week...thats the due date. if you do not know the date of you lmp, then when they due the ultra sound they will be able to measure the baby and get the due date from that.

Answer 2

First up, if they are unsure they will send you in for an ultrasound. I give my date of last period and the date of first missed, they take in to account how long your period lasts to how often you have them.
So they would guess when you ovulate? but they tell you they could be off on the dates, that it's around about sometime and not everyone goes on their due date, some go before a week or two and the baby is on time and some go over or have to be induced, and some have premature babies.
Best bet is from ultrasound, by the size and the developments.

Answer 3

Hi there dear.
Your pregnancy is always determined by the first day of your last period. You are quite right that it would be impossible to tell when a specific women ovulates which is why they use the day of your last period.
This is why that literally speaking there will always be a two week difference between how far along you really are and how far along the books and other things will say that you are.
Congratulations on your pregnancy, you have so much to look forward to!
Blessings!
Lady T~

Answer 4

I know when I ovulated and it makes a twelve day difference on my due date ( no biggie) it is a ballparrk range anyway it is 40 weeks from the last period pregnancy is ten months where in the heck did 9 months come from?? anyway do not be confused all women are different as are all cycles some women ovulate late and that makes things even crazier good luck to you!!

Answer 5

By your LMP. Well I thought I was 8 weeks one time because of my LMP. But we has an ultrasound and the gestional period was younger than my period by two weeks. So I was really 6 weeks. That is because I ovulated late. They will determine all this at your first visit, or at an ultrasound. Due dates change with time to time. So good luck.


Baby Due - (08-26-2007)

Answer 6

Because they don't know the exact date of ovulation they count from the LMP (Last Menstrual Period).

After that they typically check the gestational age by ultrasound between 8-12 weeks.

Answer 7

First day of your last period. Your exactly right that they can not tell when you ovulate, that's why women who have one sexual partner one week, then another sexual partner a week after have NO way of knowing who's baby it is by dates alone. Even if you know exactly when your suposed to have ovulated, sperm lives in woman for up to 5 days, plus you could either ovulate early or late in your cycle. This is also a huge reason they give us 2 weeks before or after our due dates as our delivery date before intervention is necessary.

Answer 8

The Expected date of delivery is counted from the first day of ur last period (LMP ) provided that ur periods are fairly regular. count 9 months from it & add 7 days .that is ur EDD. If u dont know ur LMP the fetal age may be determined by sonographic measurements.

Answer 9

Count from the first day of your last period. You can go to this website, fill in the info to get your due date, and learn how they arrive at that date:

http://www.babycenter.com/calculators/duedate/

Answer 10

first day of your last period. with my son that didnt work so they took meaurments and went from there, i skipped a period before getting pregnant