I am a little confused how they calculated my due dates?

Question

I had a scan on the 25.08.06 and they said i was 10+ weeks and gave a due date of the 25.03.07. I did not know my first day of period at this point. I had another scan on the 2.11.06 and that said 21 weeks exactly. They altered my due date to the 15.03.07. My first day of my last period was 8.06.2006 so that works out at 40 weeks. Why did they put me back 10 days and when roughly did i conceive?

Answer 1

First day of last menstrual period: June 18, 2006
Estimated date of conception: Sunday, July 2, 2006
End of 1st trimester (12 weeks): Sunday, September 10, 2006
End of 2nd trimester (27 weeks): Sunday, December 24, 2006
Estimated Due Date: March 25, 2007

Pregnancy Date Calculator

Use this calculator to determine your due date or the date your baby was conceived.

To determine your due date, enter the date of your last menstrual period. If you already know your due date, you can enter that and "calculate backwards" when conception occurred. The bottom part of the form tells you how many weeks pregnant you are today or on the date of your choice. You can also determine on what date you will be the number of weeks pregnant that you enter.

Keep in mind that this calculator is based on a 28-day menstrual cycle, and might not be accurate for women whose cycle varies from that schedule.

How your due date is calculated: Your due date is estimated by adding 40 weeks (280 days) to the approximate first day of your last menstrual period. Only 5% of women deliver their babies on their projected due date, so this date should be used as an estimate - it is not an exact calculation. (Days of the week are optional. The calculator will automatically determine them.)

Good luck and Congrats!
http://healthlink.mcw.edu/article/923526...

Answer 2

Honestly, the 10 day set back doesn't really matter. Due dates are just an estimate of when the baby will be born. Only 3% of babies are born on their due date. A lot of babies are born sometimes 2 weeks early or even 2 weeks after their due date. As long as they are not changing the months on you, don't worry. If your periods are regular, you would have conceived 2 weeks after your last period.

Answer 3

Figuring out due dates are tricky since the baby is going to come when he or she wants to anyway. I just had my third child and was given December 5th as my first date, December 17th next and the baby didn't come until December 22nd! The funny thing is - I knew the exact date of conception!

I read a book during this pregnancy that stated women are pregnant for "roughly" 40 weeks. But, since every woman is different and so are the babies, doctors and midwives shouldn't give exact due dates because it creates too much anticipation and thus disappointment if you go past your due date (like I did). It suggested care providers explain that you're due "sometime in March" instead. I thought that made sense.

Answer 4

The scan at 10 weeks is more accurate to go by. The earlier you get a scan done the better or so I have been told.. With my daughter everytime I had one done they would change my due date.. She was born on March 16th which is the very first due date I recieved when the pregnancy began.. Best of Luck...

Answer 5

they should not have put you back because the first scans are more acurate than the ones later on. go by your docs due dates not teh techs if you're worried

Answer 6

They are basing this on the development of the fetus. you would have ovulated about two weeks after the end of your last period, and could have gotten pregnant after that time.