Pregnancy beyond the due date has not yet delivered, may be physiological reasons or pathological reasons, such as cervical development is not mature, expired pregnancy and so on. 1. Physiological reasons: in pregnancy beyond the expected date of delivery, but less than 42 weeks of pregnant women, is generally a normal phenomenon, because the expected date of delivery is calculated from the first day of the last menstrual period, and can not be accurate to the specific time of fertilization, so there is a certain degree of error, and it does not mean that the expected date of delivery will definitely be delivered. 2. Pathological reasons: (1) The cervix is not yet mature: it may be that the level of oxytocin in the body is low, or the ratio of estrogen and progesterone is imbalanced, and the uterine contraction stimulation reflex is weakened. The cervix has not reached the requirements for labor, so the situation of exceeding the expected date of delivery may occur. (2) Genetic factors: a certain family or individual often recurring overdue pregnancy, as well as placental sulfate esterase deficiency with recessive inheritance, etc., may lead to overdue pregnancy. In the event that the pregnancy has not been delivered beyond the due date, it is recommended to consult a doctor in time, and in the event that all the tests are normal, if there is still no response at 41 weeks, you can follow the doctor’s instructions to choose the appropriate way to induce labor.