A case-control study of trophoblastic diseases in the People's Republic of China.

A case-control study is currently under way in Beijing, People's Republic of China, involving approximately 165 patients with invasive moles or choriocarcinoma, 165 with hydatidiform moles, and 330 population controls, who were matched to the patients with invasive moles or choriocarcinoma on age and interval since last pregnancy. The interviews are focused on a number of suspected risk factors, including previous pregnancy outcomes, history of hydatidiform mole, medical factors, drug usage, family history, and diet. A brief background of the study and methods as established through a previous pilot study are given.