Genetics Northern California

Glossary

TermDescription
Human chorionic gonadotropin

Human chorionic gonadotropin (hCG) is a hormone produced by the placenta. The levels rise rapidly in early pregnancy and then decline between the 10th and 20th weeks. Second trimester maternal blood levels of hCG may be higher in a pregnancy in which the baby has Down syndrome. The level of hCG may be lower than usual in a pregnancy if the baby is affected with trisomy 18 or SLOS.