I. The importance of fetal heart monitoring 1, can be more objective to determine the intrauterine safety and danger of the fetus, to provide the correct clinical decision-making. 2, in today’s increasingly aggressive doctor-patient conflict, must provide more auxiliary basis to prove the correct treatment, and fetal heart monitoring chart in obstetrics is one of the most important and most common evidence. 2, several basic definitions 1, fetal heart rate baseline: refers to the average of fetal heart rate over 10 minutes in the absence of fetal movement and no uterine contractions influence. The normal 120-160 bpm. 2. Oscillation amplitude of fetal heart rate: refers to the height of the up and down oscillation wave of fetal heart rate, the normal value of its variation is 10-25 bpm. 3. Oscillation frequency of fetal heart rate: refers to the number of fetal heart fluctuations in 1 minute, the normal is ≥6 times. 4, the transient change of fetal heart rate: after stimulated by fetal movement, contraction, palpation and sound, the fetal heart rate temporarily accelerates and slows down, and then returns to the baseline level, called -. It is divided into two conditions: acceleration and deceleration, which are important indicators to determine the fetal well-being. 3. Methods of predicting intrauterine reserve capacity 1. reactive type ① baseline fetal heart rate 120-160 bpm; ② at least 3 fetal movements accompanied by accelerated fetal heart rate within 20 minutes; ③ fetal heart rate acceleration amplitude ≥15 bpm and duration ≥15 seconds during fetal movement; ④ baseline fetal heart rate long-term variability amplitude 6-25 bpm and cycle 3-6 times M min. (5) The usual spontaneous contractions do not show decelerations, except for the “V” decelerations (type-o-dip) with fetal movement. If there is no fetal movement and acceleration during the monitoring time, and the fetus is awakened by external stimulation or other methods, and the fetal movement and acceleration occurs after 20 minutes of repetition, it can still be diagnosed as reactive type. 2, unresponsive type ①baseline fetal heart rate >160bpm or <120bpm; ②no fetal movement or no fetal heart rate acceleration during 20-40 minutes of monitoring, no significant fetal heart rate acceleration after stimulation; ③with fetal heart rate baseline long-term variability is reduced or disappeared, the amplitude is less than 5bpm, the cycle is less than 3 M minutes; ④fetal wake and sleep cycle is not obvious; ⑤the influence of sedative and antihypertensive drugs must be excluded. The fetal movement rarely occurs for 60 minutes without sedative or antihypertensive drugs. 3.Suspicious type Any one of the following should be classified as NST suspicious type: ①Only 1 or more fetal movements with accelerated fetal heart rate within 20 minutes; ②Fetal heart rate acceleration amplitude <15 bpm and duration <15 seconds; ③Decreased baseline variability; ④Fetal heart rate baseline 120-160 bpm; ⑤The presence of spontaneous variability deceleration. Meaning and evaluation 1. responsive type ① Fetal central nervous excitation during fetal movement → physiological reflex fetal heart rate ↑ indicates good intrauterine condition, suggesting good fetal central nervous system development, and more than 99% of fetuses are safer within one week. ② However, pseudo-response type exists in high-risk pregnancy, especially in hyperemesis, overdue pregnancy and FGR. ③ Repeat NST times, 1-2 times per week. ④ Combined BPS, ultrasound and umbilical artery blood flow test. ⑤ If necessary, CST to detect intrauterine reserve function of the fetus. 2. Non-responsive type ① Suggest fetal distress, about 20% of fetuses with non-responsive NST have poor prognosis. However, maternal sedation, fetal sleep, gestational age <37W, prolonged supine, starvation, and fetal central nervous system malformation should be excluded. The non-responsive type itself is not an indication for surgery, but the presence of NST non-responsive type with ↓ fetal heart rate or calm type at baseline represents a great danger to the fetus and should be treated promptly. (3) Pay attention to the pseudo-nonresponsive type, which accounts for about 2.1%. ④Review NST after BPS or oxygen infusion ⑤Decelerated NST is related to umbilical cord abnormality, low amniotic fluid, and giant baby; ⑥Sinusoidal fetal heart rate Fetal heart rate baseline 120-160 beats/min with regular wave-like oscillation, oscillation amplitude 5-10bpm, no reactivity of normal fetal heart rate difference. Fetal heart can be present in cases of severe anemia and high volume heart failure, severe hypoxemia and acidosis, maternal application of narcotic sedation, amnionitis, etc., which is a sign of near fetal death. Diagnostic criteria of contraction stress test: 1. negative - no late decelerations and obvious variable decelerations, suggesting good placental function and no risk of fetal death within a week; 2. positive - more than 50% of contractions have late decelerations and the frequency of contractions is less than 3 times in 10 minutes. 3.Suspicious positive - with intermittent late decelerations or obvious variable decelerations; 4.Suspicious hyperstimulation - contraction frequency >1 time/2 minutes, or duration of each contraction >90 seconds, and each contraction with fetal heart decelerations. Significance and evaluation ①When the fetus has a certain compensatory function, the momentary decrease in oxygen supply during contractions does not cause changes in fetal heart activity. ②When the fetus has chronic hypoxemia such as hyperemesis, overdue pregnancy ICP, FGR, umbilical cord factor, low amniotic fluid, abnormal umbilical cord contractions O2 ↓ in the fetus → parasympathetic excitation → late deceleration or variable deceleration. ③When the fetus has severe hypoxia and is in a state of near death → no responsiveness to external stimuli → baseline rate is calm. ④4% of persistent contractions can occur and should be closely observed. ⑤Emphasize dynamic monitoring. (6) Fetal heart monitoring and umbilical cord abnormalities The diversity of fetal heart monitoring graphics when the umbilical cord is entangled depends on whether the umbilical cord is compressed or not, resulting in severe or transient fetal hypoxia. The fetal heart monitoring observation is important 1. Signs to be continued: If one of the following signs appears in the monitoring, it should be the object of continued observation: ① Early deceleration type appears at the beginning of labor. ② Baseline fluctuation of fetal heart rate at 160 beats/min or around 110-120 beats/min. (3) Those who are prone to supine hypotension syndrome. ④Late decelerations are occasionally seen in mildly variable decelerations. ⑤ Late decelerations that can disappear after changing position or oxygenation. (6) Contractions are too strong (intrauterine pressure >55-80mmHg) and too frequent (5-6 contractions/10′). 2. Warning signs: Any one of the following is suspected of fetal hypoxia and fetal distress: ① Progressive increase in baseline fetal heart rate, especially 170-180 beats/min. ②No acceleration accompanied by fetal movement for 1-2 consecutive hours (except with sedation and anesthetics). ③Signs of frequent mildly variable decelerations (frequent > 30% of contractions) that gradually progress to severe. ④A late decelerated type, either large or small, tachycardia may be present or absent. 3, Severe signs: equivalent to fetal hypoxemia, that is, the fetus may have tissue metabolic disorders, the signs are: ① Progressive deceleration of the fetal heart rate from the normal range to 100 beats/min or progressive increase in speed >180 beats/min at baseline. ②Late decelerations occur three times in a row or frequently >20% in the presence of normal contractions ③Variable decelerations gradually increase or frequently >30% ④Late decelerations or variable decelerations combined with reduced or absent variants ⑤Decelerated NST with CST(+) ⑥Sinusoidal