Failure of fetal monitoring at 30 weeks may be caused by physiological phenomena, fetal distress and other reasons. Fetal heart monitoring is a commonly used auxiliary examination in obstetrics, which can continuously observe the dynamic changes of fetal heart rate. Usually start monitoring at 34 weeks, when there is fetal growth restriction and other comorbidities can be carried out in advance of the fetal heart monitoring, 30 weeks of pregnancy monitoring needs to be combined with the gestational week and the specific circumstances to determine the monitoring situation. 1. Physiological phenomenon: when the fetal sleep cycle can also suggest that the fetal monitoring is not pass, can be appropriate to extend the time of fetal monitoring or give appropriate stimulation can be improved, this is a normal physiological phenomenon. 2. Fetal distress: can also lead to fetal cardiac monitoring failed, by low-flow oxygen, change position, rehydration and other intrauterine resuscitation treatment without significant improvement, ultrasound suggests that fetal umbilical cord blood flow abnormalities, by experienced doctors to fully assess, clear fetal distress or high suspicion of the need for timely termination of pregnancy to ensure the safety of mothers and infants. When the fetal monitoring at 30 weeks of gestation does not pass the test, it is necessary to have a professional analysis and judgment by an obstetrician.