Final answer:
The key difference between threatened abortion and inevitable abortion is cervical dilation.
Step-by-step explanation:
Threatened abortion and inevitable abortion are two terms used to describe different types of pregnancy loss. In threatened abortion, the pregnancy is at risk but there is a possibility that it may continue. Inevitable abortion, on the other hand, refers to a pregnancy loss that cannot be prevented and will result in miscarriage.
When comparing threatened abortion to inevitable abortion, one of the key differences is cervical dilation. Inevitable abortion is characterized by the thinning and dilation of the cervix, which prepares the body for the expulsion of the embryo or fetus. This is not typically seen in threatened abortion.
Therefore, the correct answer is option C: Cervical dilation.