Natural history of twin pregnancy with complete hydatidiform mole and coexisting fetus

To investigate the clinical features and natural history of twin conceptions consisting of complete hydatidiform mole and a coexisting fetus.

Since 1973, eight well-documented cases of twin pregnancy with complete hydatidiform mole and coexisting fetus have been treated at the New England Trophoblastic Disease Center (NETDC). The clinical features of these eight patients were compared to 71 patients with singleton complete hydatidiform mole treated at the NETDC and with the published experience of other investigators. Flow cytometric analysis of DNA content was performed in addition to histologic inspection to assist in confirming the diagnosis of twin pregnancy with complete hydatidiform mole and coexisting fetus.

Five of the eight patients in this series developed persistent gestational trophoblastic tumor requiring chemotherapy. Three of these five patients developed metastases requiring multi-agent chemotherapy to achieve remission. The presenting symptoms of twin pregnancy with complete hydatidiform mole and coexisting fetus were similar to those in patients with a singleton complete mole. However, compared to singleton complete molar gestation, a twin pregnancy with complete mole and coexisting fetus was diagnosed at a later gestational age, had higher preevacuation beta-hCG levels, and had a greater propensity to develop persistent gestational trophoblastic tumor.

Our findings indicate that patients with complete hydatidiform mole and coexisting fetus are at high risk for developing persistent gestational trophoblastic tumor.