When u have and ultrasound to dermine your due date. from what point does the doctor count? Conception or ?

Question

implantation in the womb

Answer 1

Lmp

Answer 2

Last Menstrual Period if you know it...

Answer 3

What the previous poster said, but had to add that conception and implantation in the womb is the same thing.

Answer 4

In a dating ultrasound they will measure the baby and estimate how many weeks you've "been pregnant."  While everyone knows you were not pregnant at the time of your last menstrual period, but in the medical profession that's the time that they begin counting from, since it can be very hard to know a conception date, even when you know the day you had s*x (sperm can live in the body for up to seven days in fertile quality cervical fluid).  So they will date it back to your last menstrual period, assume that this happened 14 days before conception (unless you have very short cycles, in which case they may account for this) and then count forward 40 weeks to your due date.

Answer 5

they always ask from your last mestrual period

Answer 6

Neither. From your last period.  When the ultrasound is done, they measure the fetus to see if it matches your last period date.

Answer 7

The ultrasound uses the size/development of the baby to determine your due date. A dating ultrasonds is normally only done if you don't KNOW when you conceived or when your LMP was.  

Answer 8

when they do a ultrasound to figure your due date it is because in the first 12 weeks basically all babies grow the same so they measure from the head to the butt.  This gives them a number that is however many weeks then you have to count backwards to figure your Last menstral period first day, but it will give you a fairly accurate due date and it becomes your date from that time forward, it is the most accurate.

Answer 9

Unless stated otherwise, gestational ages are always assumed to be based on a theoretical LMP.  In other words, it's measured from LMP, with the ASSUMPTION that LMP was 14 days before ovulation.

Answer 10

Your ultrasound is not to determine the due date it is to determine the size of baby but the doc go by LMP