Final answer:
Cervical dilation does not typically occur in a missed abortion, where the fetus has deceased or not developed, but the body has not expelled it, with uterine contents retained.
Step-by-step explanation:
In the case of a missed abortion, cervical dilation does not typically occur. A missed abortion is a situation where the fetus has died or has not developed but has not been physically expelled from the uterus. In this type of abortion, the pregnancy is essentially over, but the cervix remains closed, and the uterine lining has not been shed, largely because the body has not yet recognized the loss of the pregnancy. On the other hand, with an incomplete abortion, threatened abortion, and inevitable abortion, cervical dilation usually occurs as part of the process where the body is preparing to expel the contents of the uterus.