Effect of Intramuscular Administration of Dexamethasone on the Duration of Labor: Randomized Controlled Trial

Abstract

abor induction with prostaglandin F2 alpha was known since 1960. Subsequently, formulations of prostaglandin E2 (PGE2, dinoprostone) were developed which largely replaced the use of F2 alpha. Cortisol increases the production of prostaglandins in the fetal membranes by either up regulating prostaglandin synthesis (PGHS-2) levels or down regulating 15-hydroxy prostaglandin dehydrogenase (PGDH). In humans, the placenta synthesizes CRH, and the exponential rise of this hormone in maternal plasma correlates with the timing of birth. Recently, CRH has been shown to stimulate placental production of estrogens and to inhibit placental synthesis of Progesterone. The increase in the maternal estrogen to progesterone ratio may promote the expression of contraction-associated proteins in the myometrium, thus facilitating the initiation of parturition. Also, glucocorticoids induce the production of CRH by the placenta and the production of prostaglandins (PGF2 and