Cervical dilation is the dilation (widening) of the cervix during childbirth. In the final stages of pregnancy, the cervix may already have opened up to 1-3 cm, but during the first stage of labour, repeated uterine contractions lead to rapid further widening of the cervix to 10 cm.

The pain experienced during dilation is similar to that of menstruation (although markedly more intense), as period pains are thought to be due to the passing of endometrium through the cervix.