What is NST examination

NST examination generally refers to stress free testing, which is a prenatal examination method used to evaluate fetal intrauterine reserve capacity and health status. The stress free test (SEP) mainly determines whether the fetus is at risk of hypoxia by monitoring the correlation between fetal movement in the uterus and changes in fetal heart rate. During the examination, pregnant women usually need to lie in a semi recumbent or lateral position, and the doctor will place a fetal heart rate probe and a uterine pressure probe in the abdomen to continuously record for 20 to 40 minutes. Under normal circumstances, the fetal heart rate will have a significant acceleration response after fetal movement, indicating that the fetal central nervous system and autonomic nervous system have good regulatory functions. If the fetal heart rate does not increase or does not increase significantly after fetal movement, it may indicate the risk of intrauterine hypoxia, umbilical cord entanglement, placental dysfunction, etc. The results of stress free testing are divided into reactive, suspicious, and non reactive types. Reactive type usually indicates good fetal condition, while suspicious or non reactive type requires further evaluation, such as uterine contraction stress testing or biophysical scoring. This examination is generally carried out after 32 weeks of pregnancy, especially for pregnant women with high risk factors such as pregnancy hypertension, diabetes, fetal growth restriction, etc. Pregnant women should avoid fasting, emptying their bladder, and maintaining a relaxed state before the examination to reduce false positive results. If the examination results are abnormal, the doctor will combine the specific conditions of the pregnant woman, such as gestational age, amniotic fluid volume, fetal size, etc., to comprehensively determine whether it is necessary to terminate the pregnancy early or strengthen monitoring. Non stress testing is a non-invasive and safe examination method, but it cannot completely rule out all fetal abnormalities, so it needs to be evaluated together with other prenatal examination results. When conducting stress free tests, pregnant women should try to choose a time period with frequent fetal activity for examination, such as after meals or when fetal movement is active, to improve the accuracy of the examination. If you feel uncomfortable during the examination, you can promptly inform the doctor to adjust your position. Pregnant women should pay attention to regular prenatal check ups, monitor changes in fetal movement, maintain a balanced diet and moderate activity, and avoid overexertion and emotional fluctuations. If there is a significant decrease or disappearance of fetal movement, seek medical attention immediately instead of waiting for the next stress free test. In addition, stress free testing is only a part of prenatal examination and cannot replace other items such as ultrasound examination and umbilical blood flow monitoring. Pregnant women should follow medical advice to complete the full set of prenatal screening to ensure maternal and infant safety.