Subsequent pregnancy outcome in patients with spontaneous resolution of HCG after evacuation of hydatidiform mole: comparison between complete and partial mole

This study compared subsequent pregnancy outcome in patients with complete and partial hydatidiform moles. Among 1052 patients with molar pregnancy (complete mole, 801; partial mole, 251) monitored at Chiba University Hospital between 1981 and 1999, 891 patients (84.7%) had spontaneous resolution of human chorionic gonadotrophin (HCG) after mole evacuation, and 161 patients (15.3%) required chemotherapy. Of the 891 patients, 438 (49.2%) had 650 subsequent pregnancies. The pregnancy outcome was not significantly different in patients with complete and partial moles, and was comparable with that in the general Japanese population. The incidence of repeat molar pregnancy in patients with complete and partial mole (1.3 and 1.5% respectively) was 5-fold higher than that of the general population, while no increased risk of persistent gestational trophoblastic tumour (GTT) associated with later molar pregnancy was observed. During HCG follow-up, 10 patients (1.1%) developed secondary high-risk GTT between 14 and 54 months after mole evacuation. The incidence of high-risk GTT in patients with and without subsequent pregnancies was 0.46% (2/438) and 1.8% (8/453) respectively (P = 0.1243). In conclusion, patients with complete and partial mole can anticipate a normal future reproductive outcome, and pregnancies after experiencing hydatidiform mole may not affect the development of high-risk GTT.