Changes in peripheral hormone levels after therapeutic abortion.

Plasma levels of progesterone, 17 alpha-OH progesterone, hPL and beta-subunit hCG were measured in a group of women for 24 h after therapeutic abortion. Progesterone, hCG and hPL levels fell more rapidly than 17 alpha-OH progesterone levels. This might suggest that the main site of synthesis of 17 alpha-OH progesterone is probably in the corpus luteum of pregnancy or that the prolonged half-life of hCG maintains the corpus luteum to secrete longer. Human placental lactogen fell dramatically within 4 h but the hCG level was maintained. This difference probably reflects only the differences in half-lives of these hormones.