Effect of Prolonged In Vivo Administration of Progesterone in Pregnancy on Myometrial Gene Expression, Peripheral Blood Leukocyte Activation, and Circulating Steroid Hormone Levels

Abstract

The observed effects of prolonged in vivo administration of progesterone will minimize the ability of the uterus to contract as a synctium and the ability of peripheral blood leukocytes to migrate into the myometrium during parturition. We suggest that these are putative mechanisms by which progesterone might prevent preterm birth in women at high risk.

Perinatal outcome in women treated with progesterone for the prevention of preterm birth: a meta‐analysis

“…As for the second hypothesis, accepting that infection would be the main cause for preterm birth in singletons vs uterine stretch in twins, the effectiveness of progesterone would depend on its ability to reduce uterine excitability. Many36, 37, but not all38, studies indicate that progesterone may indeed induce uterine quiescence through a multitude of mechanisms, from alteration of the electrical activity of the uterine muscle to alteration of gene expression and peripheral leukocyte activation.…”

Evaluation of Liver Enzymes for the Prediction of Viremia in Asymptomatic Chronic HBV Infected Pregnant Women (“Elena” Study)

“…There are also reports that present leukocytosis with marked left shift in the myeloid-neutrophilic lineage during the third trimester of normal uncomplicated pregnancy that normalized readily after delivery [19]. It has been reported that the elevated circulating levels of progesterone, especially during the late second and third trimester of pregnancy results in the increased numbers of circulating neutrophils while decreasing lymphocyte proportions, a phenomenon frequently observed in normal pregnancy [20]. Moreover, it has been reported that pregnant women exhibit lower lymphocyte counts than non-pregnant women [21].…”

The Th1:Th2 Dichotomy of Pregnancy and Preterm Labour

“…There is also in vivo evidence of an anti-inflammatory effect of prolonged administration of vaginal progesterone. In a study of pregnant women receiving either progesterone or placebo from 24 to 34 weeks, peripheral blood leukocytes were collected before and after treatment [138]. mRNAs of the proinflammatory cytokines IL-1 β and IL-8 were reduced with progesterone treatment, whereas the anti-inflammatory IL-10 was increased.…”