Beta-Human Chorionic Gonadotropin (beta-hCG)
Beta-human chorionic gonadotropin (beta-hCG) is a hormone produced by the placenta during pregnancy. It serves several important purposes in medical assessment:
- Pregnancy Confirmation: Beta-hCG is commonly used to confirm pregnancy. Elevated levels of beta-hCG in urine or blood indicate the presence of pregnancy. It's the hormone detected by home pregnancy tests as well as laboratory-based tests.
- Monitoring Pregnancy Progression: Beta-hCG levels typically rise rapidly in early pregnancy and peak around 8-11 weeks before gradually declining. Serial measurement of beta-hCG levels can be used to monitor the progression of pregnancy, confirm viability, and assess the risk of complications such as miscarriage or ectopic pregnancy.
- Assessment of Ectopic Pregnancy: In cases of suspected ectopic pregnancy, where the fertilized egg implants outside the uterus (usually in the fallopian tube), beta-hCG levels may be monitored closely. Abnormal or slower-than-expected rise in beta-hCG levels may indicate an ectopic pregnancy, which requires immediate medical attention.
- Diagnosis of Trophoblastic Disease: Trophoblastic diseases, such as gestational trophoblastic neoplasia (GTN) and hydatidiform mole (molar pregnancy), are conditions characterized by abnormal growth of placental tissue. Beta-hCG levels are typically elevated in these conditions. Serial beta-hCG measurements are used in the diagnosis, treatment monitoring, and follow-up of trophoblastic diseases.
- Screening for Down Syndrome and Other Chromosomal Abnormalities: In some cases, beta-hCG levels, along with other markers such as alpha-fetoprotein (AFP) and unconjugated estriol (uE3), are measured as part of prenatal screening tests to assess the risk of chromosomal abnormalities, particularly Down syndrome (trisomy 21).
- Detection and Monitoring of Testicular and Ovarian Cancers: Elevated beta-hCG levels may be found in certain cancers, including testicular germ cell tumors (such as choriocarcinoma) and ovarian germ cell tumors. Beta-hCG levels are monitored before and after treatment to assess response to therapy and monitor for recurrence.