[Changes in index-F and index-delta 4P in normal pregnancy, labor and the puerperium].

Index-F and index-delta 4P (cortisol and progesterone which are not bound to corticosteroid-binding globulin (CBG) in the umbilical cord vein and the maternal blood were determined during pregnancy, at delivery and puerperium. Index-F and index-delta 4P were calculated as the total cortisol or total progesterone X% unbound to CBG divided by 100. The level of index-F showed a gradual rise during pregnancy, and in late pregnancy reached about 1.5 times as high as that of non-pregnant women, whereas the total cortisol level was about 3.3 times. Near delivery, index-F was almost completely stable, but at delivery, it increased suddenly in proportion to the rise in the total cortisol level. This rise is probably due to stress. In the umbilical cord vein blood, the level of index-F was 1.5 times higher than that in the maternal plasma before delivery; however the total cortisol level was lower than that of the maternal plasma. The levels of both index-delta 4P and total progesterone showed a gradual increase during pregnancy in parallel, and each value in late pregnancy was about 4.5 to 4.9 times that of early pregnant women. At or near delivery, the level of index-delta 4P was almost stable and no decrease occurred. In the umbilical cord vein plasma, the levels of index-delta 4P and total progesterone were extremely high. However, the meaning of these results isn't clear.