what are the causes of gestational trophoblastic disease?
['Complete hydatidiform moles. In complete hydatidiform moles, a sperm cell fertilizes an abnormal egg cell that has no nucleus (or chromosomes). ... ', 'Partial hydatidiform moles. ... ', 'Invasive moles. ... ', 'Choriocarcinomas. ... ', 'Placental-site trophoblastic tumor. ... ', 'Epithelioid trophoblastic tumors.']