Preinduction cervical ripening: basis and methods of current practice

The rate of women undergoing labor induction is increasing, primarily because of patient-physician preferences. The widespread availability of preinduction cervical ripening agents has contributed to this rising trend. Approximately half of all women undergoing an induction of labor will have an unfavorable cervix that will require some ripening agent. Pharmacologic and mechanical dilator techniques have been proven to ripen the unfavorable cervix. A topically applied prostaglandin product, containing either dinoprostone or misoprostol, is the most popular means to soften and dilate the cervix. Any uterine hyperstimulation may be reversed by administering a tocolytic drug and, if possible, by removal of the ripening agent. A minimum trial of adequate labor is necessary before considering the induction to be a failure. Cesarean delivery rates may be higher and the length of hospital stay more prolonged. Careful consideration about the need for labor induction is recommended until prospective clinical trials can better validate marginal reasons for cervical ripening.