Once your cervix has started to dilate and efface, labor is approaching. However, if you are just 1 to 2 centimeters dilated, or below 50 percent effaced, it could still be days or weeks before labor actually starts.

Is effacement a good indicator of labor?

Why Effacement Is Essential

When actual labor begins, the contractions really start to stretch the cervix. First-time moms may labor longer because they tend to efface before they dilate. But, in later pregnancies, effacement and dilation usually happen together and more quickly.

Can you be 100% effaced and not in labor?

This probably isn't the answer you want to hear, but you can be varying degrees of dilated or effaced for several days — or even weeks — before true labor begins. Alternatively, you might not be dilated or effaced at all and still go into labor within hours. First-time moms tend to efface before they dilate.