The due date is calculated based on the last menstrual period, not the time when the pregnancy was discovered. If the last menstrual period is in the first half of March, the due date will be in December, and if the last menstrual period is in the second half of March, the due date will be at the end of December or the beginning of January of the second year. It is normal to give birth within two weeks before or after the due date. If the birth occurs between the 24th and 36th weeks of pregnancy, it is considered premature, and if the birth occurs after the 42nd week, it is considered late. If a pregnant woman has passed her due date and has not yet shown signs of labor, she must pay attention to the following points: 1, pay attention to fetal movement: fetal movement monitoring is the best means of self-monitoring in late pregnancy, which can reflect the survival of the fetus in the womb, if the fetal movement is less than 3 times per hour or less than 20 times in 12 hours or fetal movement is weakened, you need to go to the hospital immediately for further examination; 2, continue to conduct maternity examinations: the early pregnancy The result of the examination and the time and result of fetal movement will be told to the doctor, so that the doctor can check the pregnancy week again; 3. Strengthen prenatal examination: shorten the interval of examination, keep in touch with the doctor and inform the fetal movement in the uterus, meanwhile ultrasound check the amount of amniotic fluid. If there is no abnormality, the pregnancy can be continued under close supervision. If the due date is postponed to 14 days later and reaches what is clinically called overdue pregnancy, timely measures should be taken at the hospital.