38 weeks pregnant in the evening frequent fetal movement, usually a normal phenomenon during pregnancy, due to the night environment is quieter, the fetus is more active, and environmental interference is less, fetal movement is also easy to be detected. In addition may also be due to other circumstances, can be based on the specific circumstances of the comprehensive judgment of the cause. 1, maternal factors: pregnant women in the night after bathing or eating, emotional reprieve, happy mood, may make the fetus fetal movement increase. In addition, if pregnant women drink coffee, strong tea and other beverages, may increase fetal excitability, resulting in frequent fetal movement; 2, fetal factors: the frequency, rhythm and intensity of fetal movement of different fetuses are different, if the daily count of fetal movement are more, and the time stage of the fetal movement is closer to the time, it may belong to the natural laws of the fetus; 3, pathological factors: in general, the number of fetal movement in the hour 3-5 times, if more than Normal value belongs to abnormal fetal movement, need to consider the possibility of intrauterine hypoxia. If the monitoring of fetal heart sound, showing fetal heart sound <120 beats/min or >160 beats/min, belongs to the fetal heart sound abnormality, in addition to the need to carry out fetal heart monitoring, if the fetal heart monitoring suggests that the baseline variance is poor, occasional or frequent deceleration, it may be a manifestation of fetal hypoxia, and need to be actively dealt with, so as not to cause fetal distress or even intrauterine death of the serious consequences.