At 38 weeks of pregnancy, most primigravid women have already entered the pelvis. In cases such as menstruation and cephalopelvic disproportion, the pelvis may not have yet entered the pelvis, and it is recommended to determine this through four-step palpation. Pelvic insertion means that the head of the fetus partially or completely enters the pelvic inlet plane, and it usually occurs at 38 weeks of pregnancy. However, there are individual differences in the time of pelvic entry, and some pregnant women may not be in pelvic entry at 38 weeks of pregnancy. Some pathologic causes such as pelvic stenosis, macrosomia, abnormal fetal position and other causes of cephalopelvic disproportion may lead to late or even difficult pelvic entry. Whether or not the baby is in the pelvis is usually determined by the obstetrician performing a four-step palpation, which can be done by holding the baby’s first sign above the pubic symphysis and swaying it from side to side, or by pressing deeply behind the pubic symphysis in the direction of the pelvic inlet. It is recommended that people in the late stages of pregnancy should take obstetric checkups on time, and deal with any abnormalities in a timely manner to ensure the health of both the mother and the child.