The cervical canal is 18mm. The exact time of delivery depends on the regularity of contractions and the size of the gestational week, and cannot be generalized. If the cervical canal is only 18mm at less than 37 weeks of gestation, it is important to rest in bed and not to do strenuous exercise to prevent the risk of preterm labor. If the contractions are irregular, the degree of disappearance of the cervical canal alone cannot be evaluated, and it should be combined with the number of weeks of pregnancy and contractions. 37-40 weeks of labor is normal, and if the pregnant woman is not sure, she can be admitted to the hospital on time to wait for delivery, during which she can climb stairs and exercise moderately to speed up the labor process. However, if the number of weeks of pregnancy is short, it may be necessary to go to the obstetrics department of the hospital, take early treatment of fetal preservation and bed rest to avoid preterm delivery. Therefore, it is recommended to do regular pregnancy checkups during pregnancy and go to the obstetrics department of the hospital to communicate with the doctor in time if you find any discomfort.