Gestational Age VS Fetal Age and the time of conception

[funnyone]

Hi - I am new to this forum and I really need some help! My husband and I have been TTC for many years and finally after attemping to give up we got PG. Now I have a few questions for the EXPERT out there. I am trying really hard to determine when I got PG... But I am haveing a hard time doing so. Let me give you some history first. The first day of my LMP was on 07/03/06 (full blood on 07/04/06). I get a period every 33 days (sometimes between 31-35 days) on average 33 days. Ok... so now the story starts. I went to the doctor for two ultrasounds.

My first US was on 08/19/06. The US stated that there was only a gestational sac with a yolk - with no fetal pole noted. The age of the fetus was based upon two dates. One: Gestational Age of LMP @ 6 Weeks 4 days and the other was just a Gestational Age based upon the size (9.7mm x 4mmx4.2mm) @ could correspond to 5 weeks.

My second US was on 08/31/06. The US stated that there is a gestational sac, yolk sac and fetal pole noted. The age of the fetus was again based upon two dates: Gestational Age of LMP @ 8 weeks 2 days and the other was based upon the Gestantional Age @ 6 weeks 5 day +/- 3 days. With notes stating that the CROWN RUMP LENGTH fetal pole is @ 0.9 cm corresponding to 6 weeks 6 days.

Can someone help me by telling me if the gestational sac meansurments and the crown rump measurements are based upon:

I understand the term of Gestational Age LMP. But I am confused with the term "gestational age". Is the gestational age based upon the 14 day rule that every woman ovulated 11-15 days after their LMP? HELP!

[luv_babies]

Gestational age is from LMP. Fetal age is usually about two weeks behind, (~from conception). I have the book "Your Pregnancy Week by Week" and it has gestational and fetal age every week. I am 15 weeks from LMP, but the fetus is only ~13 weeks. Sounds as if everything is going well for you!

[funnyone]

I am just trying to figure out how to make sence of all of this. everyone keeps saying gestational age is two weeks later. But i clearly have a doc that states GALMP AT 8-2DAYS & GA at 6-6DAYS.

[luv_babies]

Everything I have read was geastational age (from LMP) and fetal age (~ovulation). Most drs go by LMP anyway, I wouldn't stress about it. When is your due date?

[funnyone]

due date is 4/21- which would be based upon 6 weeks 5 days i believe.   Thanks again! :0)

[luv_babies]

Sorry can't help more. maybe ask your about the difference? Congratulations!

[justlittleolme]

the ultrasound measurments edd is based on averages... here they tend to rely on it more than the lmp since the lmp is also based on a textbook cycle and ovulation.

[mumwith#4]

Hey - congratulations! I am due with #4 on 04/11/07 and am currently 9 weeks 2 days (today). The gestational age of the fetus is 2 weeks less than this by my understanding (and previous experience lol)!