title: Serum progesterone, estradiol, and estriol before and during induced labor.
abstract: To investigate the association of serum levels of progesterone (P), estradiol (E2), and estriol (E3) with the initiation of regular contractions, venous blood samples were taken prior to and 3 hours after the successful induction of labor in 83 parturients by means of low amniotomy and intravenous oxytocin infusion. The serum P level and P/E2 ratio decreased and serum E2 level increased after induction in healthy primigravidas and in parturients with an initial P dominance (serum P/E2 ratio more than 5). There was also a decrease in the serum P level and P/E2 ratio in postterm patients and parturients with a ripe cervical state. Cholestasis of pregnancy was associated with a rise in the serum level of E2 and a decrease in the P/E2 ratio. In an unfavorable cervical state there was a rise in the serum E2 level; patients with an initial E2 dominance (serum P/E2 ratio 5 or less) showed a rise in the serum P level and P/E2 ratio. Healthy multigravidas and patients with pre-eclampsia did not show any hormonal changes. The onset of induced labor seems to be associated with a rise in serum E2 concentration and/or with a drop in P concentration. The increase in serum E2 level is thought to be due to the activation of the anterior pituitary--adrenal axis. The lower P level is supposedly a result of diminished uteroplacental circulation.
mesh_terms: D002584:Cervix Uteri / Q000502:physiology; D004958:Estradiol / Q000097:blood*; D004964:Estriol / Q000097:blood*; D005260:Female; D006801:Humans; D007751:Labor, Induced; D010298:Parity; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood; D011374:Progesterone / Q000097:blood*
chemical_list: D011374:Progesterone; D004958:Estradiol; D004964:Estriol