The role of prostaglandins E1 and E2, dinoprostone, and misoprostol in cervical ripening and the induction of labor: a mechanistic approach
INTRODUCTION Labor induction is now reported to occur in up to 30 - 40% of obstetrical patients. There are a number of pharmacological options available to facilitate labor induction, including oxytocin and analogues of prostaglandins E1 and E2, which have particular utility when labor induction necessitates cervical ripening, as when labor induction occurs in the context of an unfavorable cervix. AREAS COVERED This paper reviews acceptable pharmacological options for labor induction, especially when cervical ripening is required. These options include oxytocin and a number of prostaglandin formulations using dinoprostone and misoprostol. It also covers several analyses of published clinical trials (Phase-III) describing evidence of effectiveness. EXPERT OPINION Oxytocin is best used when labor needs to be induced in the context of a favorable cervix. When the cervix is not favorable, cervical ripening using prostaglandins should precede labor induction. Either dinoprostone or misoprostol are superior to oxytocin alone for cervical ripening. However, judicious, careful considerations need to be made at the outset of labor induction so as to balance maternal and fetal risks, and these should be guided by institutional policies that reflect the evidence-base.