Closed at the beginning of delivery, the cervix will gradually change appearance, fade, expand and open under the effect of contractions to let the baby.
Why and how to measure cervical dilatation?
- In late pregnancy, the cervix is shortened and begins to open (usually a space equivalent to the width of a finger). Under the pressure of the child's head and the influence of contractions, the cervix changes its appearance. With each contraction, the walls of the uterus pull the cervix upward, allowing it to gradually open. As long as the dilatation of the cervix is not complete, the baby can not go out.
- The canal which, inside the cervix, connects the body of the uterus to the vagina, progressively shortens to become confused with the rest of the uterus: it is said that it is erased, but it does not is still half-open.
- In a second step, it will expand to match the diameter of the child's head. The dilatation thus goes from 1 to 10 cm: moment when the engagement of the baby in the basin can begin. The speed of dilatation of the cervix is most important. Normal or fast, it shows a good prognosis. If it stops or trails, it's a sign of a problem.
- The midwife appreciates the opening of the cervix with a vaginal touch. It has 1 cm for a finger, 2 cm for two fingers, 3 cm for two fingers apart. Then, it evaluates the space that exists to the sides of the neck.
- At 10 cm, the cervix has the same diameter as the uterus itself: the dilatation is complete.
An examination not necessarily pleasant
- Without being painful, this examination is not necessarily very pleasant and one takes care to practice it outside periods of contraction which are already quite uncomfortable.
- The vast majority of women support a dilation of 3 to 4 cm without much difficulty. Beyond that, the contractions are getting closer and the pain becomes more intense. But differences exist depending on whether it is a first child or a second child. It also depends on whether or not the water pocket has been broken off right away. The sensation remains much less painful for a second child.