<P> Cervical dilation (or cervical dilatation) is the opening of the cervix, the entrance to the uterus, during childbirth, miscarriage, induced abortion, or gynecological surgery . Cervical dilation may occur naturally, or may be induced by surgical or medical means . </P> <P> In the later stages of pregnancy, the cervix may already have opened up to 1--3 cm (or more in rarer circumstances), but during labor, repeated uterine contractions lead to further widening of the cervix to about 6 centimeters . From that point, pressure from the presenting part (head in vertex births or bottom in breech births), along with uterine contractions, will dilate the cervix to 10 centimeters, which is "complete ." Cervical dilation is accompanied by effacement, the thinning of the cervix . </P>

Another name for opening up of the cervix during childbirth is