Final answer:
A threatened abortion is characterized by spotting without dilation of the cervix.
Step-by-step explanation:
The type of abortion characterized by spotting without dilation of the cervix is known as a threatened abortion. In a threatened abortion, there may be signs that suggest a miscarriage could occur, such as bleeding, but the cervix remains closed and the pregnancy continues at least temporarily. It is important to differentiate between this and other types of abortion, such as complete, spontaneous, and missed, which are characterized by different clinical manifestations.