Cervical Dilation & Effacement

The cervix is a 3-4 cm long "bottleneck" opening of the uterus that protrudes into your upper vagina. It remains, in most women, hard, closed and long until the end of the pregnancy. Towards the end of the pregnancy, it softens. The baby_s head, due to gravity and early pre labor contractions, will press down on the cervix and gently open and shorten it. This opening of the cervix is called _dilation_ and the shortening, also knows as the thinning of the cervix, is called _effacement_. Early in the pregnancy the cervix is 0 percent effaced (meaning not shortened at all) and when it has totally effaced, it is 100 percent effaced. When there is some dilation and/or effacement going on, the mucus plug that has been there since the beginning of the pregnancy will soften and often come out. At times the plug might be mixed with blood and is then called _bloody show_. If you are less than 37 weeks pregnant and you notice your mucus plug coming out or signs of bloody show, do notify your health care provider since it can be a sign of preterm labor. Effacement in first time mothers, will often occur before dilation occurs. In comparison to women who have already had a baby where dilation will often start before the cervix has totally effaced. Your health care provider can, by doing a manual vaginal examination, determine the softness of your cervix and if you are starting to dilate or efface.