Cervical ripening. A review and recommendations for clinical practice.

Cervical ripening occurs before the onset of labor. The cervix is metabolically active during ripening and passive during active labor. A ripe cervix indicates readiness for labor and predicts successful induction of labor. Practitioners evaluate cervical readiness for labor using the Bishop score. Membrane stripping, mechanical dilators and prostaglandins are ripening methods used frequently because they are simple, effective, efficient, safe and well tolerated. Stripping of membranes, a Foley catheter and misoprostol tablets are less expensive than other available methods. Because prostaglandins may cause excessive myometrial activity and even labor, hospitalization and fetal monitoring are recommended. Despite their effectiveness, these methods often do not decrease the cesarean section rates. This finding may be explained by the fact that each study reviewed only included a small number of patients and that in most cases, amniotomy was done and induction started, when feasible, before the women reached a Bishop score > or = 9. Larger studies may have different outcomes. The type of ripening methods used depends on the urgency of the situation; balloon catheters and prostglandins often act within 12 hours, while membrane stripping is less predictable.