to study the changes in steroid concentrations in amniotic fluid ( af ) in relation to the initiation of parturition , eleven steroids in af which included cortisol ( f ) , progesterone ( p4 ) , 20 alpha-dihydroprogesterone , free ( f- ) and conjugated ( c- ) pregnenolone , dha , estradiol ( e2 ) and estriol ( e3 ) were measured by ria .
C0033308
progesterone
C0012311
20 alpha-dihydroprogesterone