<Li> Complete: 10 centimeters . Delivery of the infant takes place shortly after this stage is reached (although the mother does not always push right away .) </Li> <P> During pregnancy, the os (opening) of the cervix is blocked by a thick plug of mucus to prevent bacteria from entering the uterus . During dilation, this plug is loosened . It may come out as one piece, or as thick mucus discharge from the vagina . When this occurs, it is an indication that the cervix is beginning to dilate, although not all women will notice this mucus plug being released . </P> <P> Bloody show is another indication that the cervix is dilating . Bloody show usually comes along with the mucus plug, and may continue throughout labor, making the mucus tinged pink, red or brown . Fresh, red blood is usually not associated with dilation, but rather serious complications such as placental abruption, or placenta previa . Red blood in small quantities often also follows an exam . </P> <P> 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 . Most of the pain during labor is caused by the uterus contracting to dilate the cervix . </P>

What is dilation of the cervical os prior to uterine contractions called ​