Progesterone and threatened abortion: a randomized clinical trial on endocervical cytokine concentrations

The purpose of this study was to investigate the effect of vaginal progesterone on endocervical cytokine concentration in women at risk of threatened abortion. One hundred and sixty pregnant women with clinical symptoms of threatened abortion before the 20th week of pregnancy were randomly assigned to receive vaginal progesterone or placebo. Cervical fluids were collected and endocervical concentrations of different cytokines (IFNγ, TNFα, IL-8, IL-10 and IL-12) were analyzed before and one week after progesterone or placebo treatment. A significant decrease in IFNγ and increase in IL-10 in endocervical fluid was seen when the values were compared before and after progesterone treatment. However, there were no significant differences in pregnancy outcomes between the placebo and progesterone groups. We conclude that despite the failure of vaginal progesterone treatment to improve pregnancy outcomes, progesterone can induce a shift in the concentration of cytokines in endocervical secretions.