SERUM HUMAN CHORIONIC-GONADOTROPIN CLEARANCE CURVES IN PATIENTS WITH INTERSTITIAL PREGNANCY TREATED WITH SYSTEMIC METHOTREXATE

Objective: To evaluate short-term effectiveness of systemic methotrexa te (MTX) in interstitial pregnancy. Design: Case series. Setting: Two Dutch teaching hospitals. Patient(s): Eight consecutive patients with an unruptured interstitial pregnancy, Intervention(s): Four doses of 1 .0 mg/kg IM MTX alternated with 0.1 mg/kg oral folinic acid. Serum hCG concentrations were determined before the first MTX injection and fol lowed until levels were undetectable. A second MTX course was started on day 14, if by then serum hCG concentrations were > 40% of the initi al value. Serum hCG clearance curves of all patients in the present st udy were compared with those from our earlier studies, in which a diff erent folinic acid regimen (15 mg orally) was used. Main Outcome Measu re(s): Serum hCG clearance curves. Result(s): All patients were treate d successfully: five with one course and three with two courses. Serum hCG clearance curves of these patients tended to decline more rapidly than those successfully treated with the 15 mg folinic acid regimen. Conclusion(s): Systemic MTX is an attractive therapeutic option in the conservative treatment of unruptured interstitial pregnancy. The regi men of four doses of 1.0 mg/kg IM MTX alternated with 0.1 mg/kg folini c acid is effective. Serum hCG clearance curves may serve as a guideli ne for monitoring MTX treatment, thus enabling a timely detection of i mpending treatment failure.