Human chorionic gonadotropin, or hCG, is often called the pregnancy hormone. According to MedlinePlus, a service of the U.S. National Library of Medicine, hCG is a hormone produced during pregnancy and can be found in both the blood and urine of a pregnant woman.
Time Frame
According to the American Pregnancy Association, hCG can be found as early as 11 days after conception with a blood test and by 12 to 14 days with a urine test. HCG levels double every 72 hours in the first 8 to 11 weeks of pregnancy and then begin to drop, eventually leveling off.
Tests for hCG
MedlinePlus reports there are two types of blood tests that measure hCG and one urine test. A qualitative blood hCG test determines whether there is any hCG present in the blood while a quantitative test determines the level. These tests are done to determine pregnancy, diagnose abnormal conditions that increase levels of hCG and watch the development of the pregnancy during the first three months.
The urine test for hCG will determine pregnancy. If the test is performed too early in a pregnancy, it may produce a false negative. Retesting is advised if pregnancy is suspected.
Function of hCG
Human chorionic gonadotropin is produced by cells that form the placenta. The job of hCG early in pregnancy is to keep estrogen and progesterone at appropriate levels until the placenta can take over this function.
hCG Levels
The American Pregnancy Association cites that hCG levels of less than 5 mlU/ml indicate a negative test for pregnancy, and levels higher than 25mlU/ml are indicative of pregnancy. Human chorionic gonadotropin is measured in milli-international units per milliliters. Results from blood and urine tests reporting hCG levels should not be used to date pregnancy. Ultrasound is more accurate.
Caution
Human chorionic gonadotropin levels can be used to help determine the health of a pregnancy. It is important to note that these levels are averages and that low hCG levels can, and have, resulted in perfectly healthy live births. HCG levels should be used in conjunction with other information obtained about the pregnancy to help determine the health of the pregnancy.
