Is normal β‐hCG regression curve helpful in the diagnosis of persistent trophoblastic disease?

. Objective: The aim of this study was to evaluate the probable usefulness of normal β‐human chorionic gonadotropin (β‐hCG) regression curve in the diagnosis of persistent trophoblastic disease (PTD). Methods: A log‐value regression curve was developed from the means and 95% confidence limits of serial weekly serum β‐hCG titers of 43 patients with uneventful complete hydatidiform moles and 14 patients, who were previously confirmed as PTD. Results: All 14 PTD patients (100%) had abnormal values, beyond normal range, within 4 weeks. β‐hCG was in its upper values, compared to normal regression curve at 2.29 ± 0.19 weeks. This was earlier than plateau or rise detection at 4.21 ± 0.33 weeks (P