Understanding hCG Levels in Early Pregnancy: What's Normal?

Human chorionic gonadotropin (hCG) is a hormone produced by the developing placenta after implantation of a fertilized egg in the uterus. hCG levels can be detected in the blood or urine as early as 10-14 days after ovulation. The amount of hCG in the blood increases rapidly during the first few weeks of pregnancy, reaching a peak of around 100,000 mIU/mL by 10-12 weeks. After that, hCG levels decline gradually over the rest of the pregnancy.

A single hCG blood test can be used to diagnose pregnancy. A positive result means that hCG is present in the blood, which indicates that pregnancy is likely. However, a single hCG blood test cannot determine how far along the pregnancy is.

To determine the gestational age of a pregnancy, a quantitative hCG blood test can be performed. This test measures the exact amount of hCG in the blood. The results of a quantitative hCG blood test can be used to create a growth curve, which can help to track the progress of the pregnancy.

hCG levels can also be used to monitor the health of a pregnancy. For example, high hCG levels may be a sign of a multiple pregnancy, while low hCG levels may be a sign of a miscarriage.

If you are pregnant or think you might be pregnant, your doctor may order an hCG blood test to confirm the pregnancy and monitor its progress.