What is the normal size of the cervix?

Under normal circumstances, the cervical canal length should be greater than 3 cm, which falls within the normal range. A cervical length of less than 3 cm indicates cervical shortening, which increases the risk of complications such as miscarriage. Therefore, maintaining a cervical length within the normal range during the second trimester helps reduce the risk of miscarriage. In late pregnancy, particularly during labor, the cervical canal typically effaces completely—a normal physiological phenomenon.