Hcg is human chorionic gonadatrophin.
This is a hormone produced by the very fact that you are pregnant.
In the first few weeks your hcg levels should approximately double every 48 - 60 hours.
While a urine test will detect the presence of hcg a blood test can be quantative - meaning to tell how much hcg is present and give a fairly accurate time of pregnancy

Kia you sound smart! Good thing your'e here! :d

Lol, maybe i'm just old also I have an insatiable need for information - most of what I know is completely useless to anyone but ho hum.
Sorry not good at taking compliments - i'll try again.
Thanks pitterpatter

Don't be embarresed! I'm serious it's nice to know that someone knows what they are talking about!

Oh ok, thank's kia I think I understand a little better..Lol....So when they did the blood test and they said I had a level of so and so putting me anywhere from 9-12week's, that's what they meant by that?! I was wondering what was meant by, when they said you have a level of 27,000. Are those blood test normally accurate on hcg level's, I have read of women having normal and ab-normal hcg level's. But the way you explained it helped me understand alot more..Lol...Thank you again

Ok its a bit scientific but do scroll down a bit and there is a chart that may help

http://pregnancy.About.Com/gi/dynamic/offs ite.Htm?Site=http://www.Advancedfert ility.Com/earlypre.Htm

also note that levels decline after a peak at about 8-10 weeks.

For some reason the link doesn't work but heres the gist of it
or try cut and pate the link into your browser

long post beware
hcg levels in pregnancy

hcg, or human chorionic gonadotropin, is a hormone made by the pregnancy that can be detected in the mother's blood or urine even before the woman's missed period. This hormone is what we look for with a "pregnancy test".

Hcg is first detectable in the blood as early as 7-8 days after ovulation by very sensitive hcg assays (research assays). In real life, blood pregnancy tests will be positive (> 2 miu/ml) by 10-11 days after hcg injection or lh surge.

In general, the hcg level will double every 2-3 days in early pregnancy.

85% of normal pregnancies will have the hcg level double every 72 hours.

Hcg levels peak at about 8-10 weeks of pregnancy and then decline, remaining at lower levels for the rest of the pregnancy.

There is a large variation in a "normal" hcg level for any given time in pregnancy.

Pregnancies destined to miscarry or to be ectopic (tubal) pregnancies tend to show lower levels (eventually), but often have normal levels initially.

Some normal pregnancies will have quite low levels of hcg - and deliver perfect babies. Caution must be used in making too much of hcg "numbers". Ultrasound findings after 5-6 weeks of pregnancy are much more predictive of pregnancy outcome than are hcg levels.

For women that have had an hcg injection as part of their infertility treatment, the hormone will take about 5-14 days to clear from the woman's system, depending on the dose and the individual woman. This can causes problems with interpretation of pregnancy tests done earlier than 14 days after an hcg injection.



Hcg levels from normal singleton pregnancies

levels are listed for various days after the ovulatory hcg injection or lh surge
first (same as third) international reference preparation was used (second irp gives lower values)
"high" is highest seen in this group of pregnancies
"low" is lowest seen in this group of pregnancies
"#" is the number of tests done for that day in this group of pregnancies

these values are from a group of 53 normal singleton pregnancies (a very small group)
because this is a very small group of patients and because lab assays vary, it is important not to rely on these values to try to determine whether your pregnancy is viable, single, twin, etc.

Check with your physician about your own levels

hcg levels from normal twin pregnancies

twin pregnancies tend to show higher hcg levels on a given day of pregnancy. However, there is a large variation in hcg levels between pregnancies, and much overlap exists between single and twin pregnancies.

Levels are listed for various days after the ovulatory hcg injection or lh surge
first (same as third) international reference preparation was used (second irp gives different values)
"high" is highest seen in this group of pregnancies
"low" is lowest seen in this group of pregnancies
"#" is the number of tests done for that day in this group of pregnancies

these values are from a group of 29 normal twin pregnancies (a small group)
because this is a very small group of patients and because lab assays vary, it is important not to rely on these values to try to determine whether your pregnancy is viable, single, twin, etc.

Check with your physician about your own levels

Ok..Lol...Thank you for that response!!! Lol....Thank you for explaining it better...It really helped alot.. So when my doctor said "based" on my hcg level's I was anywhere from 9-12 week's, is that pretty accurate?? I am just worried that my baby is measuring small for week's pregnant, if I got pregnant when my blood test said I did, or in that time frame. But is it safe to kinda estimate week's by blood test??