Persistent trophoblast disease following partial molar pregnancy

Human chorionic gonadotrophin (hCG) follow-up data were analysed retrospectively in all patients registered in the Hydatidiform Mole Registry at the Royal Women's Hospital, Melbourne from January 1992 to January 2001 to determine the risk of persistent trophoblast disease following partial molar pregnancy and to review the present follow-up protocol of patients suffering from partial hydatidiform molar pregnancy (PHM).

Demographic factors were determined for all 344 cases with a review diagnosis of PHM, included age, history of previous hydatidiform mole, gestation length, hCG levels and compliance with follow-up.

Six of the 344 patients diagnosed with PHM required treatment with single-agent methotrexate and folinic acid rescue. All six patients achieved and maintained a complete biochemical remission after chemotherapy. hCG regression assays were analysed for 235 patients: 225 patients had at least one normal hCG measurement during follow-up, of whom 152 (64.7%) patients obtained normal values within 2 months after evacuation. All patients obtained normal levels within 32 weeks after evacuation of the partial hydatidiform mole. Only 63 (25.6%) patients completed the recommended follow-up program. No patient who achieved normal hCG levels required chemotherapy because of a recurrent gestational trophoblastic tumour.

This study indicates that 1.7% of all partial mole pregnancy patients needed treatment for malignant sequelae. In contrast, no patient diagnosed with partial mole had a biochemical or clinical relapse after achieving normal levels of hCG, consistent with previous studies. Patients who have had a partial hydatidiform mole should be followed by hCG assays until normal levels are achieved and then follow-up can be safely discontinued.