In normal conditions and during most part of your pregnancy, your cervix, the opening of your uterus, remains closed and tight. That is a good thing because its job is to keep your baby inside of you. At the end of gestation and during labour, the cervix begins to develop some changes to allow the baby to come out. One of these changes (and the most important one) is dilation. Dilation happens when your cervix begins to open up.

For your baby to be born, your cervix will need to have 10 cms. of dilation. This is approximately the diameter of a softball or a small bagel, or in obstetric terminology, approximately the size of your baby´s head.

You can say it has, but really it is the labour stage that has them. Dilation happens during the first stage of labour, which has 3 phases:

1. The early labour phase, which begins with the first real contractions and ends when the cervix reaches the 3 cms. of dilation,

2. The active labour phase, in which the contractions get more intense, continues the dilation from 3 to 7 cms.

3. The transition phase, which goes from 7 to 10 cms. of dilation. Obviously, this can vary from woman to woman.

It depends on each woman. Medically speaking, in primiparous women, there is a rule that indicates that for every cms. dilated, 1 hour has to pass, reaching easily the 10 to 12 hours of labour. In multiparous women, this time is reduced to half.

This can happen to many women due to a vast number of reasons: wrong pelvic shape, baby´s position, stress, induction happening prematurely, etc. Your physician will try expecting management, giving your cervix chance to dilate, or will apply active management (if appropriate), using synthetic substances to help your cervix. If none of these results, you will need to have a cC-section.