Dilation of the cervix.
The thinning or obliteration of the cervix during labor.
Flattening and extension of the cervix.
The thinning of the cervix before it dilates in childbirth.
Shortening of the cervix and thinning of its walls as it is stretched and dilated during labor.
In obstetrics, the thinning of the cervix as the internal os is slowly pulled up into the lower uterine segment.
The gradual thinning of the cervix that typically accompanies dilation in the period shortly prior to childbirth.