Having a painful menstrual sensation in the lower abdomen at 38 weeks pregnant is not an accurate way to tell how soon you will be in labor; having a painful menstrual sensation in the lower abdomen may be caused by uterine contractions after the fetus has entered the pelvis, and is not a way to tell exactly when you will be in labor. The feeling of menstrual cramps in the lower abdomen at 38 weeks of pregnancy is not directly related to how long it will take to give birth. In late pregnancy, the fetus will slowly descend into the pelvis, the descent process may cause uterine contractions, resulting in a feeling similar to menstrual cramps, the fetus into the pelvis may be 2 to 3 weeks between births, or may be in the pelvis is about to go into labor, it is difficult to determine the specific time of delivery. If the feeling of menstrual cramps in the lower abdomen at 38 weeks of pregnancy is caused by regular uterine contractions, it may enter the labor process in about 24 hours, and the interval between regular uterine contraction pains will become shorter and shorter, and the duration of the pain will become longer and longer. At this point it is time to go to the hospital for labor.