In the fifth month of pregnancy, fetal movement may become weak with the fetus in the sleep cycle, maternal fatigue, fetal intrauterine hypoxia and other factors.1, fetal sleep cycle: fetal sleep cycle is generally 20-60 minutes, sleep state fetal movement will be reduced. Fetal activity rhythms are different every day, usually more active at night, during the day will be relatively weak, pregnant mothers often feel fetal movement is not obvious during the day; 2, maternal fatigue: the baby’s fetal movement with the mother’s mood and exercise rest state, pregnant women will lead to fetal movement is not obvious; 3, intrauterine oxygen deprivation: fetal hypoxia due to a variety of reasons in the uterus, the fetal movement will be suddenly reduced, if within one hour, the number of fetal movements is less than four, the fetal movement will be reduced to four. The number of fetal movements is less than 4 times in 1 hour, and the number of fetal movements is less than 10 times in 2 consecutive hours, which indicates that the fetus may be hypoxic, and need to consult a doctor in time. Therefore, five months of pregnancy in fetal movement becomes weak, should be timely to the hospital, the use of electronic fetal heart monitoring to monitor the condition of the fetus, if the lack of oxygen is best for oxygen to improve. Daily attention to strengthen nutrition, pay attention to rest, do not excessive exercise, and regular prenatal examination.