What is effaced in pregnancy?

In pregnancy, effacement refers to the progressive shortening and thinning of the cervix, which is the opening to the uterus. It occurs as the uterus prepares for labor and birth.

During pregnancy, the cervix is typically firm, long, and closed. As labor approaches, the cervix begins to soften, shorten, and thin out, a process known as effacement. This is caused by the action of hormones such as oxytocin and prostaglandins, which relax the muscles of the cervix.

Effacement is measured in percentages, ranging from 0% to 100%. At 0% effacement, the cervix is long and thick. As effacement progresses, the cervix becomes shorter and thinner. At 100% effacement, the cervix is completely effaced, meaning that it has become almost paper-thin and has opened to about 10 centimeters (about the size of a nickel) to allow the baby to pass through.

Effacement is an important sign of cervical dilation, which is the opening of the cervix to allow for the passage of the baby during childbirth. Typically, effacement and dilation occur together, but in some cases, effacement may be more advanced than dilation, or vice versa.

Monitoring cervical effacement and dilation is part of the standard prenatal care during labor. Healthcare professionals use various methods, such as digital cervical exams, to assess effacement and dilation. These assessments help determine the progress of labor and make decisions regarding the management of childbirth.