It is possible that the fetus does not start because it is not full term, the pregnant woman is not sensitive to contractions, cephalopelvic disproportion and other possibilities. 1. the fetus is not full-term: 37 weeks of pregnancy to the fetus is full-term, if the fetus is not full-term, then it is likely that the placenta is not ripe, and the cervix is not ripe, this is not easy to cause contractions start. 2. Pregnant women are not sensitive to the contraction: women to labor start, the body will secrete a certain amount of contraction, if the female friends are not sensitive to the contraction, then it is likely to be difficult to start the situation. 3. Cephalopelvic disproportion: If the fetus is not properly articulated with the pregnant woman’s pelvis, or if the pregnant woman’s pelvis is small and the fetus is large, it will easily lead to cephalopelvic disproportion, and the articulation abnormality will not be able to form effective stimulation of the cervix, which will not be easy to induce contractions. Pregnant women should pay attention to regular obstetric examination during pregnancy, if the fetus is still not activated in late pregnancy, do not be too anxious and worried, follow the doctor’s instructions can be carried out.