The process that leads to the thinning and stretching of the cervix is referred to as cervical effacement. This is your body’s way of getting ready for the upcoming labor and delivery.
Cervix is a long tube like structure, connecting the uterus to the birthing canal. The cervix stays closed throughout the pregnancy and is firm to touch. First, it begins to soften and thin out as you approach 37 weeks and then it prepares to open up when the labor is near.
In late pregnancy, the baby moves down low into the pelvis. This is clearly visible on the outside too, as your belly appears too low. When this happens, the baby’s head adds pressure on the cervix. This makes the cervix to loosen up and start stretching. This is when effacement is said to take place. Cervical effacement usually happens when you are closer to your due date.
During pregnancy, the cervix remains sealed by mucus plug at its opening. When the effacement occurs and the cervix starts to relax, the mucus plug comes off and is discharged through vagina. Mucus plug is a thick, transparent blob of mucus. You may or may not notice the passing of mucus plug. This is sometimes tinged red with a little amount of blood and is known as bloody show. When you experience bloody show or mucus plug discharge, it means that your labor is near. It may begin soon or may take few more weeks.
The timing of effacement and dilation of the cervix differ for women to women. In some pregnancies, effacement can take a few weeks and happens at a slow pace. Where as, first time expecting moms may not experience effacement and dilation till they enter second phase of labor. When you are close to your due date, your doctor or midwife may check for the effacement by placing fingers. Effacement of cervix is usually measured in percentages. Your cervix is said to be 100% effaced, if it has thinned out completely.
The cervix also needs to dilate, apart from effacement, for the baby to pass through the birth canal. When your labor begins, the shortened and stretched out cervix starts to dilate, because of the uterine contractions. This in turn helps the baby to position itself and be ready for birth. Dilation is measured in centimetres. If it is 10, then your cervix is referred to as completely dilated. You need to be 10 cms dilated in order to begin pushing.