title: Secretion patterns of plasma-progesterone, 17-hydroxyprogesterone and 20 alpha hydroxypregn-4-en-3-one in early normal pregnancy.
abstract: Plasma levels of progesterone, 17-hydroxyprogesterone and 20 alpha hydroxypregn-4-en-3-one were established from 4 to 16 weeks gestation by sampling 15 normal patients twice weekly. Apart from a peak at week 5, the mean levels of progesterone remained constant at about 24 ng/ml until week 10 and then rose progressively to 40 ng/ml at week 16.20 alpha hydroxypregn-4-en-3-one remained within the 7 to 9 ng/ml range apart from a peak at week 5. A significant decrease in mean levels of 17-hydroxy-progesterone was noted from week 5 to a nadir of 3 ng/ml at week 11. It would appear that the main hormone production of progesterones in pregnancy has been taken over by the placental unit by the 10th week.
mesh_terms: D004092:20-alpha-Dihydroprogesterone / Q000097:blood* / Q000378:metabolism; D005260:Female; D006801:Humans; D006908:Hydroxyprogesterones / Q000097:blood* / Q000378:metabolism; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011374:Progesterone / Q000031:analogs & derivatives* / Q000097:blood* / Q000378:metabolism
chemical_list: D006908:Hydroxyprogesterones; D004092:20-alpha-Dihydroprogesterone; D011374:Progesterone