Cervical effacement

Cervical effacement or cervical ripening refers to a thinning of the cervix. This is a normal, physiologic process during the onset of labor to prepare the cervix for eventual delivery. At times, this process can occur prior to pregnancy being full term - this is called cervical insufficiency and leads to increased risk of preterm delivery.

Cervical ripening is also part of the process of induction of labor, where medical interventions such as use of prostaglandin and oxytocin medications, balloon catheters, and membrane sweeping are utilized to help start labor.

Background

Cervical effacement is a component of the Bishop score and can be expressed as a percentage.

Prior to effacement, the cervix is like a long bottleneck, usually about four centimeters in length. Throughout pregnancy, the cervix is tightly closed and protected by a plug of mucus. When the cervix effaces, the mucus plug is loosened and passes out of the vagina. The mucus may be tinged with blood and the passage of the mucus plug is called bloody show (or simply "show"). As effacement takes place, the cervix then shortens, or effaces, pulling up into the uterus and becoming part of the lower uterine wall. Effacement may be measured in percentages, from zero percent (not effaced at all) to 100 percent, which indicates a paper-thin cervix.

Results from a systematic review of the literature found no differences in cesarean delivery nor neonatal outcomes in women with low-risk pregnancies between inpatient or outpatient cervical ripening.

Effacement is accompanied by cervical dilation.