HCG Levels By Week
Human chorionic gonadotropin (HCG) is a hormone which increases at a regular rate during the early part of your pregnancy. As such, many women try to determine what's going on with their pregnancy by checking their HCG levels. HCG can be measured through blood or urine, though blood tests provide more accurate quantitative levels than urine tests. What are the normal HCG levels by week for a healthy pregnancy, and what is the significance of any deviations from those values?
At three weeks (since your last menstrual period), your HCG levels will probably be somewhere in the 5 - 50 mIU/ml range. At four weeks, they could measure anywhere from 5 - 426 mIU/ml. Do you notice the increasingly wide range? This is one of the reasons that it's hard to determine anything for certain about a pregnancy just by looking at HCG levels. You might think a particularly high or low value indicates something important, but with such a wide range, any of the values in that range can indicate a completely normal, healthy pregnancy.
At five weeks, the levels should measure between 18 - 7,340 mIU/ml. 1,080 - 56,500 mIU/ml is a normal healthy range for six weeks. Between 7-8 weeks, the range is tremendous: 7, 650 - 229,000 mIU/ml. The HCG levels peak between 9-12 weeks at 25,700 - 288,000 mIU/ml, after which they start to drop. In general, during the early stages of your pregnancy, you should notice your HCG levels doubling every 2-3 days. The rate of increase is far more important to keep track of than the actual number in most cases. If the rate isn't doubling or is decreasing, then something could be wrong. A doctor will tell you if your rate is unnaturally low and could indicate a problem.
At 13-16 weeks, your HCG levels will begin to fall, and should range between 13,300 - 254,000 mIU/ml. At 17-24 weeks, typical measurements are 4,060 - 165,400 mIU/ml. At 25-40 weeks at the end of your pregnancy, your HCG levels will probably measure 3,640 - 117,000 mIU/ml. And just in case you're wondering, if you aren't pregnant, a typical HCG range is about 55-200 ng/ml.
Keep in mind all the levels listed above are normal levels—even the high and low ends of the ranges. If your rates are high or low, you may have simply miscalculated the date of your conception. This is very common and accounts for many cases of high and low readings. You also just may be an outlier experiencing a normal, healthy pregnancy with slightly unusual HCG levels. High levels may sometimes indicate the presence of twins or multiples, or may indicate a molar pregnancy (which is a problem). Low levels may sometimes indicate ectopic pregnancy (another problem) or a miscarriage. The levels by themselves do not indicate anything for certain however and must be verified through additional testing should your physician suspect there may be something wrong. In most cases, high and low readings are innocuous.