Identification of patients with persistent trophoblastic disease by means of a normal human chorionic gonadotropin regression curve

Abstract

Data from the Dutch Central Registry of Hydatidiform Mole were used to establish a reference human chorionic gonadotropin regression curve after molar pregnancy. A normal serum human chorionic gonadotropin regression corridor was constructed after fitting data from 130 patients with uneventful human chorionic gonadotropin regression after evacuation of a complete hydatidiform mole. Retrospectively, data from 77 patients with persistent trophoblastic disease were analyzed by means of this normal corridor. Measurements were performed with a radioimmunoassay for both native and free human chorionic gonadotropin beta-subunits. Human chorionic gonadotropin disappearance curves showed a biphasic decline with median serum half-lives of 1.8 and 12.8 days. Median time until normalization was 74 days (range 28 to 430). With the 95th percentile line, 71 of 77 patients (92%) with persistent trophoblastic disease could be identified. In > 50% of cases this could be achieved within 6 weeks from evacuation. The normal regression corridor allows identification of patients with persistent trophoblastic disease and an expectant attitude within the limits of the corridor.