[Elimination of human chorionic gonadotropin in serum and urine after uncomplicated induced abortion during the first trimester].

Serum chorion gonadotropin was measured weekly in 12 women from the time of legal first trimester abortion until values were below 10 IU/L. The elimination followed a 2-component curve. The half-life in the first few days was 1.1 day, hereafter 4.2 days. Serum-HCG decreased to less than 10 IU/L within 22 to 40 days. The elimination of serum-HCG was found to decrease so uniformly, that values which do not decrease must be considered abnormal. A sensitive bedside urine-HCG test was found to be positive from 13 to 31 days after the abortion.