[Studies on the viability of trophoblast after termination of various kinds of pregnancies (author's transl)].

Although normal value of hCG (LH level) does not necessarily indicate eradication of viable trophoblast, its confirmation has been demonstrated as a clinically useful guide for the probable prevention of choriocarcinoma after hydatidiform mole by Takeuchi et al. Choriocarcinoma preceded by other pregnancies than hydatidiform mole which has the highest risk for choriocarcinoma has drawn more attention than before in connection with the decrease of postmolar choriocarcinoma. So that I have studied the regression rate of urinary gonadotropin (hCG) after the termination of various kinds of pregnancies. In 2,433 cases of induced abortion, 695 cases of spontaneous abortion, 1,724 cases of term delivery and 43 cases of hydatidiform mole, their urinary hCG were determined to the level of physiological range of LH. The rate of hCG regression was in the order of term delivery, spontaneous abortion, induced abortion and hydatidiform mole. The younger was the gestational age of trophoblast, the slower was the regression of hCG. At one month after the termination of pregnancy, 80.1%, 11%, 0.3%, 8% and 4.1%, and at two month 55.8%, 1.6%, 0.5%, 4% and 0.5% for hydatidiform mole, induced abortion of less than 12 week of gestation, spontaneous abortion of less than 12 week of gestation, spontaneous abortion of between 13 and 20 week of gestation respectively still showed abnormal hCG value. One percent of induced abortion at 5 month, 4% of spontaneous abortion at 3 month, 0.3% of term delivery at 4 month still maintained abnormal titer. No malignant sequelae in patients under the investigation have ever been observed in the follow up period between 3 and 8 years.