The Uterus - a Progesterone Target Organ

Progesterone is a steroid hormone synthetized from pregnenolone, a derivate of cholesterol, produced by the yellow body of the ovary and by the placenta during pregnancy. It is crucial for the evolution of the pregnancy, from preconception until delivery. It prepares the endometrium for implantation, supresses the immune response, inhibits the myometrium's contractility and it can also make the myometrium sensitive to the action of beta-mimetic tocolytics. The vaginal administration of progesterone in various doses has proved effective in preventing premature birth in pregnant women with short cervix 25mm during transvaginal ultrasound exam.