I suggest that you discuss this issue with your OB/GYN. HCG levels are not really a good estimation of how far along you are. We use the HCG levels for a few different diagnostic tests. The first one is that if it's positive, you're pregnant. That's why the home pregnancy tests simply measure whether or not HCG is present in your urine. The quantitative HCG is not so important in and of itself, but rather the rate at which it rises is important. A rapidly rising HCG level indicates a healthy pregnancy whereas early on a falling level might indicate miscarriage. Later on in pregnancy, we use the HCG level along with a few other tests to risk stratify your baby to the likelihood of having Down's syndrome. This test is optional. After a certain point in your pregnancy, the HCG level stops rising. For these reasons, it is not a good indicator of how far along you are.
Please discuss this issue with your OB/GYN. He or she can discuss the ways in which your pregnancy is dated. Prior to your 8-9 week ultrasound
, your pregnancy will likely be dated based on the first day of your last menstrual period. After that, it will likely be dated based on the baby's size on that first ultrasound. Good luck!