sorry this will be a long post, i'm cutting and pasting! here's what i found on
http://www.conceivingconcepts.com/learn ... s/hcg.html :
There is a large variation in a "normal" HCG level for any given time in pregnancy. Caution must be used in making too much of HCG "numbers." Ultrasound findings after five or six weeks of pregnancy are much more predictive of pregnancy outcome than are HCG levels. You won't expect to see a gestational sac or the fetus until the HCG level reaches at least 1,200 mIU/ml.
However, a single HCG level cannot indicate a normal pregnancy. In a normal pregnancy there is a regular increase of the HCG, so you need to see more than one value before you can better understand what's going on. Additionally, a single value cannot always tell you how far along the pregnancy is, because of the wide range of blood HCG levels in pregnancy. To illustrate the limitations of looking at a single measurement, here is a sample reference list for HCG levels in singleton pregnancies, based on days past ovulation (DPO):
* At 14 DPO, the average HCG level is 48 mIU/ml, with a typical range of 17-119 mIU/ml.
* At 15 DPO, the average HCG level is 59 mIU/ml, with a typical range of 17-147 mIU/ml.
* At 16 DPO, the average HCG level is 95 mIU/ml, with a typical range of 33-223 mIU/ml.
* At 17 DPO, the average HCG level is 132 mIU/ml, with a typical range of 17-429 mIU/ml.
* At 18 DPO, the average HCG level is 292 mIU/ml, with a typical range of 70-758 mIU/ml.
* At 19 DPO, the average HCG level is 303 mIU/ml, with a typical range of 111-514 mIU/ml.
* At 20 DPO, the average HCG level is 522 mIU/ml, with a typical range of 135-1690 mIU/ml.
* At 21 DPO, the average HCG level is 1061 mIU/ml, with a typical range of 324-4130 mIU/ml.
* At 22 DPO, the average HCG level is 1287 mIU/ml, with a typical range of 185-3279 mIU/ml.
* At 23 DPO, the average HCG level is 2034 mIU/ml, with a typical range of 506-4660 mIU/ml.
* At 24 DPO, the average HCG level is 2637 mIU/ml, with a typical range of 540-10,000 mIU/ml.
Accordingly, the key to interpreting the true value of HCG measurements is to look at their progression. In general, the HCG level will double every two to three days in early pregnancy. Approximately 85 percent of normal pregnancies will have the HCG level double every 72 hours. However, as you get further along in your pregnancy and the HCG levels get higher, the expected doubling time increases.
* For HCG levels <1200 mIU/ml, the expected doubling time is 48-72 hours.
* For HCG levels 1200 to 6000 mIU/ml, the expected doubling time is 72-96 hours.
* For HCG levels >6000 mIU/ml, the expected doubling time is >96 hours.
HCG levels peak at about eight to 10 weeks of pregnancy and then decline, remaining at lower levels for the rest of the pregnancy. Here is a sample listing of expected HCG levels based on time after conception:
* 0-1 week: 0-50 mIU/ml
* 1-2 weeks: 40-300 mIU/ml
* 3-4 weeks: 500-6,000 mIU/ml
* 1-2 months: 5,000-200,000 mIU/ml
* 2-3 months: 10,000-100,000 mIU/ml
* 2nd trimester: 3,000-50,000 mIU/ml
* 3rd trimester: 1,000-50,000 mIU/ml
* Non-pregnant females: <5.0 mIU/ml
* Postmenopausal females: <9.5 mIU/ml
although i have no idea what this actually means!!![/quote]
