How to determine the fetal heart rate monitoring chart

Many pregnant mothers are confused when they get the fetal heart rate monitoring report. They don't understand the data and graphs on it. They personally think it is quite good, but it is a different story when the doctor explains it in detail. So how do pregnant women understand the fetal heart rate monitoring chart? How to judge the fetal heart rate monitoring chart? How do pregnant women understand fetal heart rate monitoring charts?

Method/Process

Fetal heart rate monitoring is the general name for the fetal heartbeat, fetal movement and uterine contraction graph. It uses a fetal heart rate electronic device, an electrocardiogram, to record the fetal heart rate curve and uterine contraction pressure waveform for clinical analysis. It can grasp the fetal heartbeat response during fetal movement and uterine contraction to infer whether the fetus in the uterine cavity is lacking oxygen. It is an important test method to accurately assess the intrauterine condition of the fetus. Fetal heart rate monitoring usually starts at 32-36 weeks. If there is a history of miscarriage or the fetal heart rate monitoring fails, it will be advanced to 28 weeks. Generally, the time for fetal heart rate monitoring will be determined according to your condition, and the time depends on your personal situation.

There are mainly two channels in fetal heart monitoring. The upper one is the fetal heart rate, which fluctuates between 110-160 beats/minute under normal circumstances. After the baby's fetal movement, the fetal heart rate may accelerate briefly, exceeding 160 beats / minute, but it will recover soon. This is a sign of good fetal health. If the fetal heartbeat exceeds 160 times per minute, or is less than 110 times per minute, or the heart rate is irregular, sometimes fast, sometimes slow, sometimes skipping, or there are gaps in the middle, it is abnormal. The lower line indicates the intrauterine pressure, which only increases when the uterus contracts and then remains around 20 MmHg. A comprehensive fetal heart rate monitoring score of 8 or above is considered to be up to standard. A score of 6-7 may indicate a problem of insufficient oxygen, and a fetal heart rate monitoring should be conducted again to comprehensively check the results.

There are three main parameters in fetal heart monitoring to determine whether the pattern is normal: baseline rate, gene variation and regular changes.

1. Baseline rate: It refers to the fetal heart rate when there is no fetal movement and no uterine contraction, which lasts for more than 10 minutes. This has a different meaning from the traditional stethoscope. A stethoscope listening to the fetal heart rate at ≥160 and ≤110 beats/minute can confirm intrauterine distress. Although the fetal heart rate recorded by fetal heart monitoring for a period of time is ≥160 beats/minute, due to various influencing factors, the result is tachycardia. A heart rate of ≤110 beats/minute indicates bradycardia. You should also pay attention to whether sedatives, anesthetics, etc. are used, and whether the fetal head is under pressure in the pelvis. Of course, a heart rate that is too fast or too slow should be taken seriously, and more attention should be paid to changes in the heartbeat. For example, a gradual increase in the baseline heart rate or an idiopathic decrease are both changes that are precursors to severe hypoxia, metabolic acidosis, or intrauterine fetal death.

2. Gene variability: refers to the regular dynamic response of two independent central nervous systems to heartbeat regulation. Only when they function normally will they fluctuate within a certain range. The absence of short gene variants may occur in severe intrauterine ischemic hypoxia. However, like the baseline rate, the simple reduction, vertical or excessive increase of baseline gene variants to predict intrauterine hypoxia has a high false positive rate, and other important parameters must be observed.

3. Regular changes: refers to whether there is an acceleration response in NST with the baby's fetal movement. The commonly used definition of reactive NST is: at least 3 fetal movements accompanied by an acceleration of the fetal heartbeat within 20 minutes, the intensity of which is ≥15 seconds, and the duration is ≥15 seconds. If the above acceleration response does not appear within 40 minutes, it is a non-reactive type.

In addition to fetal heart monitoring once a week, you should also count fetal movements at home at other times. There must be more than 3 fetal movements per hour. If the baby is not active, you should continue counting for several hours to comprehensively observe the results. For example, if the number of fetal movements is less than 20 times after 12 hours, you should pay attention. For those who find it inconvenient and don't want to count fetal movements, you can perform fetal heart monitoring at home, so that you can understand the physical condition of the fetus without leaving home.