In hydatidiform mole, which hormone is characteristically elevated?

• A. Human chorionic gonadotropin (hCG)
• B. Estrogen
• C. Progesterone
• D. Testosterone

Answer: (A)

Hydatidiform mole causes abnormal growth of placental trophoblastic tissue that massively secretes a pregnancy hormone. The cells that form the outer layer of the chorionic villi—the syncytiotrophoblasts—produce a lot of human chorionic gonadotropin. When trophoblastic tissue proliferates widely as in a mole, the circulating hCG levels rise far beyond those seen in a normal pregnancy. This dramatic elevation in hCG explains many characteristic features, including intense nausea and potential hyperemesis, and it can even trigger hyperthyroidism in some cases because hCG can weakly stimulate the TSH receptor. Estrogen and progesterone are elevated in pregnancy but don't show the same distinctive, excessive rise in a mole, and testosterone is not involved in this process.