Question: how common is gestational trophoblastic disease?
Answer: Gestational trophoblastic disease (GTD) occurs in about 1 pregnancy out of 1,000 in the United States. Most of these are hydatidiform moles. Choriocarcinoma , a malignant form of gestational trophoblastic disease (GTD), is even less common, affecting around 2 to 7 of every 100,000 pregnancies in the United States.