fetal distress
Introduction
Introduction to fetal distress Fetal distress refers to the syndrome of fetal hypoxia caused by various high-risk factors such as pregnant women, fetuses or placenta, and acidosis, which often endangers the health and life of the fetus. Fetal distress is the main cause of perinatal death. Therefore, early diagnosis and early treatment of fetal distress to reduce perinatal morbidity, morbidity and mortality are important topics for obstetric clinicians. basic knowledge The proportion of illness: the incidence rate of pregnant women is about 0.001%-0.002%, mostly related to intrauterine hypoxia Susceptible population: pregnant women Mode of infection: non-infectious Complications: cerebral edema, cerebral hemorrhage, neonatal hypoxic ischemic encephalopathy
Cause
Causes of fetal distress
Maternal factor (35%):
Insufficient blood supply to small arteries, insufficient oxygen carrying capacity of red blood cells, acute blood loss, impaired blood supply to the uterus, emergency delivery or uncoordinated contraction of the uterus. Improper use of oxytocin causes excessive contractions. Prolonged labor, especially the second stage of labor. The uterus is over-expanded, the membrane is prematurely broken, and the umbilical cord may be stressed.
Umbilical cord, placenta factor (20%):
Placental dysfunction caused by diseases such as umbilical cord blood flow obstruction or expired pregnancy, placental developmental disorders (too small or too large), abnormal placental shape (membranous placenta, contoured placenta, etc.) and placental infection.
Fetal factors (25%):
Fetal cardiovascular system dysfunction, such as intracranial hemorrhage of severe congenital cardiovascular disease. Fetal autologous malformations.
Prevention
Fetal distress prevention
Intrauterine distress can directly endanger the health and life of the fetus. Therefore, regular prenatal checkup is very important, and timely detection of abnormalities in the mother or fetus, such as pregnancy-induced hypertension syndrome, chronic nephritis, expired pregnancy, placental aging, anemia, fetal developmental delay, placenta previa, combined with heart disease, etc. In order to determine the degree of harm to the fetus, develop a corresponding treatment plan to prevent or treat it. Pay attention to self-care during pregnancy, increase nutrition, work and rest, avoid bad habits, and prevent placental abruption. Seek medical attention if you feel unwell and have reduced fetal movement. Intrauterine distress for treatment failure, such as near term, not in labor, the extrauterine environment is better than the uterus, early termination of pregnancy, do not wait.
Complication
Fetal distress complications Complications Cerebral edema cerebral hemorrhage Neonatal hypoxic ischemic encephalopathy
The main complications are cerebral ischemia in the fetus, hypoxia-induced cerebral edema, brain cell necrosis, cerebral hemorrhage and life-threatening, and should be diagnosed and treated early.
Symptom
Fetal distress symptoms Common symptoms Embryonic development, blood supply, lack of amniotic fluid, fecal infection, meconium, fetal movement, frequency, amniotic fluid, turbid pregnancy, high umbilical cord, short anal sphincter relaxation
symptom
The main clinical manifestations of fetal distress are: abnormal fetal heart rate changes, amniotic fluid pollution and fetal movement abnormalities, clinical manifestations of fetal distress, fetal heart rate changes, amniotic fluid fecal infection and fetal movement changes are common clinical manifestations, but not unique to fetal distress.
1. Changes in fetal heart rate
The tachycardia 160-180 beats/min is the initial signal of fetal distress. This phase lasts for a short time. With the increase of hypoxia, the fetal heart rate gradually slows down to 119-100 beats/min, and arrhythmia occurs. Bradycardia is more pronounced, fetal heart rate is 99 times/min, heart sound is strong and weak, and finally the heart rate is getting slower and slower, the arrhythmia is more serious, the heart sound is gradually weaker and weaker, the fetus is in a state of sudden death, and finally The heartbeat stops and the fetus is dead.
2. Amniotic fluid
When the fetus is hypoxic, it often causes reflexive anal sphincter relaxation, and the intestinal peristalsis is enhanced, so that the meconium is discharged and caused by amniotic fluid. However, there is amniotic fluid in the amniotic fluid, and there is no need for fetal distress. In recent years, it has passed the full-term animal test and Observed by pregnant women, meconium excretion may increase intestinal excitability due to intestinal hormones, which is a normal physiological manifestation of fetal maturation. Therefore, amniotic fluid fecal infection is not a specific manifestation of intrauterine distress, and it must be comprehensively analyzed during labor. According to the dynamic observation of the early fecal staining and fecal staining of amniotic fluid, it is still an early signal of fetal distress.
3. Fetal movement changes
The number of fetal movements varies greatly, generally fluctuating between 30 and 100 times / 12 hours. Many factors can affect fetal movement. For example, pregnant women lying down, sound, light stimulation and abdominal touch can increase fetal movement, but fetal movement is reduced. About half of them are caused by intrauterine distress. Therefore, the feeling of pregnant women can be used as an indicator to judge the intrauterine status of the fetus. For example, the number of fetal movements within 10 hours is less than 10 times, indicating that the fetus is hypoxic, generally less than fetal movement per hour. At 3 times, you should be alert to the possibility of hypoxia and distress in your fetus.
classification
Chronic fetal distress
It occurs mostly in the end of pregnancy and often continues to be labored and aggravated. The reason is mostly caused by maternal systemic diseases or pregnancy-induced diseases caused by placental insufficiency or fetal factors. Clinically, in addition to the presence of maternal disease causing insufficient blood supply to the placenta, intrauterine growth retardation occurs with prolonged fetal chronic hypoxia.
2. Acute fetal distress
Mainly occurs during childbirth, mostly due to umbilical factors (such as prolapse, around the neck, knotting, etc.), placental abruption, excessive contractions and long duration, and maternal low blood pressure, shock and so on. Clinical manifestations in fetal heart rate changes, amniotic fluid meconium contamination, fetal movement frequency, fetal movement disappeared and acidosis.
Examine
Fetal distress check
Amniotic fluid monitoring
The fetus lives in the amniotic fluid. Due to the special close relationship between the amniotic fluid and the fetus, the abnormality of the amniotic fluid and its amount can be used to understand the fetal hypoxia and determine the safety of the fetus.
(1) Monitoring of amniotic fluid volume: The clinical manifestation of amniotic fluid reduction is that the height of the uterus and the abdominal circumference are smaller than the pregnancy month. The abdominal uterus is tightly wrapped around the carcass, lacking the sense of amniotic fluid, limited fetal activity, and an anoxic environment. Estimating the amount of amniotic fluid is one of the important signals to judge the safety of the fetus. The less amniotic fluid, the higher the incidence of fetal distress and neonatal asphyxia, the higher the amplitude of QRS wave detected by fetal electrocardiogram.
Judging the amount of amniotic fluid, B-ultrasound is usually used to observe the size of the dark area of amniotic fluid:
1 Maximum sheep pool depth (AFV) determination: AFV refers to the vertical depth of the largest amniotic fluid dark zone without umbilical cord, which is (5.1±2.1) cm in the late pregnancy, AFV>8cm is too much amniotic fluid, <3cm is amniotic fluid Less, 2cm is too moderate, 1cm is too small.
2 Determination of amniotic fluid index (AFI): The vertical depth of each pond is measured according to the four quadrants of the pregnant woman's abdomen. The sum of the four quadrants is the amniotic fluid index. Usually, AFI 5cm is too little amniotic fluid, and 5-8cm is less amniotic fluid. 10~24cm is normal. AFI can correct the one-sidedness of AFV only measuring the depth of a single sheep pool, and the clinical detection effect is better.
(2) Amniotic fluid meconium pollution degree: normal amniotic fluid should be colorless and slightly turbid liquid. When the fetal blood oxygen content drops below 30%, the neonatal adverse outcome is significantly increased, accompanied by meconium discharge, according to meconium The degree of pollution can determine the severity of fetal hypoxia. Clinically, B-ultrasonography, amniocentesis or rupture of membranes to observe amniotic fluid traits is used as an indicator for judging intrauterine hypoxia.
1 amniocentesis: is an endoscopic technique for observing amniotic fluid from the cervical canal through the fetal membrane in the third trimester of pregnancy. According to the watery condition of the sheep, fetal intrauterine distress can be detected early.
The characteristics of amniotic fluid in late pregnancy or childbirth are divided into 4 degrees: I degree (normal): amniotic fluid is colorless, transparent or milky white, showing fetal fat or fetal hair; II degree (suspicious): amniotic fluid is translucent, pale yellow or Light green, faintly visible fetal fat or fetal hair; III degree (abnormal): amniotic fluid yellow or light green, turbid opaque, not easy to see fetal fat and fetal hair; IV degree (severe abnormality): amniotic fluid is yellow or dark green, sticky and turbid opaque.
Clinical observation: After rupture of the membrane, if the amniotic fluid II degree indicates that the fetus may be hypoxic; II degree above indicates that the fetus is severely hypoxic, which may be acute fetal distress; III degree indicates that the fetal hypoxia has exceeded 6h, and is in a critical state.
2 Clinical significance of amniotic fluid fecal staining: Clinical observation confirmed that amniotic fluid fecal infection is closely related to fetal hypoxia. In high-risk pregnancy, the incidence of amniotic fluid fecal infection is significantly increased, and the degree of fecal staining is significantly correlated with umbilical venous oxygen saturation, but There is also amniotic fluid fecal infection and neonatal outcomes are good. In this regard, amniotic fluid fecal infection may be caused by other non-hypoxia factors. According to statistics, full-term amniotic fluid has 10% to 15% of fecal stains. It accounts for 25% to 50%, which indicates that as the fetus matures, the tension of the vagus nerve increases and causes gastrointestinal motility. The discharge of fetal meconium into amniotic fluid may be a normal physiological phenomenon. The study also found that there is biliary red in amniotic fluid. It is also known that there are more intestinal enzymes in the intestines of the late pregnancy. There is a peristalsis and defecation in the intestines of the fetus, and amniotic fluid is caused by the amniotic fluid. At present, the academic community has disputed the diagnosis of amniotic fluid as a basis for the diagnosis of fetal distress, to a large extent It is not possible to correctly estimate the time and discharge of meconium discharge, and estimate the criteria for the pre-natal meconium discharge time based on histopathological features:
A. Macrophages filled with pigment can be seen in the amniotic membrane tissue, and the meconium discharge is 1 to 3 hours from birth time.
B. Macrophages filled with pigment were found in the villus tissue, and the meconium excretion time was about 3 hours from birth.
C. Fetal nails have meconium contamination, and meconium discharge time is 4 to 6 hours from birth time.
3 Judgment of amniotic fluid feces: The meconium discharge time should be divided into early and late stage. Early meconium discharge means that meconium contamination is found during the active or ruptured period of labor; the late meconium discharge means that amniotic fluid is clear before. In the second stage of labor, meconium contamination was found. Early mild amniotic fluid fecal dyeing accounted for 54% of amniotic fluid fecal staining. There was no significant difference between neonatal outcome and amniotic fluid meconium staining, while early severe amniotic fluid fecal infection accounted for about 25%. It is associated with fetal heart abnormalities and other obstetric factors that cause neonatal abnormalities. Neonatal outcomes are poor, even in fetal death; late amniotic fluid meconium contamination accounts for about 21%, and neonatal asphyxia is significantly increased. Therefore, amniotic fluid is contaminated. Whether the fetus is abnormal, the most important thing is to judge the time and amount of meconium discharge, and pay enough attention to the early severe amniotic fluid meconium pollution.
In short, due to the different mechanism of amniotic fluid meconium staining, the clinical status of sheep can not be used alone as a diagnostic basis for fetal hypoxia or only as an indication of cesarean section, but amniotic fluid feces should not be ignored, according to amniotic fluid The degree and appearance period, combined with other monitoring indicators, is still a direct and simple monitoring method in the identification of intrauterine distress. It is a warning signal for predicting intrauterine hypoxia.
2. Cord blood monitoring
Umbilical blood monitoring during pregnancy can reflect the true state of fetal acid-base balance or imbalance, and has a high diagnostic accuracy for fetal distress. The pH of normal fetal umbilical vein blood is lower than that of the mother, PCO2 is higher, PO2 is decreased, and fetal plasma is The buffer base (BBP) and BE values are similar to those of maternal blood. From the graphical analysis of the acid-base equilibrium equation, the fetus should be classified as "respiratory acidosis".
(1) Collection method of umbilical cord blood during pregnancy: Under the guidance of B-ultrasound, the umbilical vascular puncture is performed through the abdomen of the mother, and the umbilical vein blood is taken out with a heparinized syringe to seal it 2 to 4 ml, and the umbilical cord puncture site is:
1 1 cm from the root of the placenta;
2 from the umbilical fossa 1cm;
3 randomly selected free segment, but usually fixed at the root of the placenta or the umbilical fossa of the fetus, the puncture is easy to succeed.
Umbilical vascular puncture can be performed from 18 weeks of gestation to full-term pregnancy, with the best pregnancy from 20 to 22 weeks. Due to the high requirements of umbilical cord puncture and blood collection, there is a certain risk, the bleeding rate is 23 to 37%; the incidence of fetal loss 0.8% ~ 1.6%, pregnant women are generally not easy to accept, but compared with placental puncture, fetal mirror blood collection, has a relatively safe and simple advantages, suitable for prenatal diagnosis, and opened up a new way for intrauterine treatment.
(2) Blood collection method after childbirth: When the newborn is born before breathing, the two vascular clamps are used to clamp a umbilical cord, and the heparinized syringe is used to extract 1 to 2 ml of umbilical vein blood, respectively, and immediately after sealing, the umbilical cord blood is passed. The analysis can objectively reflect the newborn's condition at birth:
1 Reasons for fetal distress:
2 Evaluation of the effects of various pathological conditions on acid-base balance and oxygen supply.
3 to guide the treatment of neonatal asphyxia.
4 determine the prognosis of the newborn.
(3) Judging indicators of intrauterine hypoxia: umbilical venous blood P02 <2.53 kPa, pH < 7.2, maternal and child blood pH difference > 0.20.
3. Biochemical monitoring comprehensive score
Due to the advancement of biochemical detection methods in recent years, especially the development of radioimmunoassay, the research on placental hormones, enzymes and certain specific proteins has turned from laboratory to clinical, and has been applied to the monitoring of fetal-placental function to become a treatment for fetal distress, high-risk pregnancy. a basis for this.
(1) Examination of placental hormones:
1 Estradiol determination: The production of estriol (E3) during pregnancy is the result of the cooperation of fetal-placental function. The urinary E3 value increases with the progress of pregnancy, reaching the highest value at 38 to 39 weeks of pregnancy, and after 40 weeks of gestation. The decline, its measurement can determine the fetal physiological state and placental function, because the measured value is affected by the specific gravity of the urine, the concentrated urine E3 content is high, the diluted urine content is low, so the clinical use of urine estrogen (E) / creatinine (C) ratio In place of the measurement, the amount of C excretion in the urine of pregnant women is relatively constant, and E/C represents the number of milligrams (mg) of estrogen discharged per 1 g of creatinine. The advantage is that it can replace all urine of 24 hours with a single urine or partial urine. The urine output is counted again, but the first urine in the morning is close to the 24h urine E/C. The judgment of the measured value: normal value: E/C>15, suspicious value: E/C 10-15, dangerous value: E/ C<10, but the E value in blood and urine fluctuated greatly within 24 hours, and there were many interference factors, and there was a false positive rate. Therefore, other indicators should be combined to judge the fetal prognosis.
2 blood placenta prolactin (hPL): hPL structure is similar to human growth hormone, blood hPL concentration in early pregnancy is 500 ~ 1000 times early, half-life is short, 20 ~ 30min, can quickly reflect the functional status of the placenta, is the placental function One of the good methods of examination, the judgment of hPL measurement value: <4mg / L suggests that the placental function is low, but the placental compensation function is very strong, even if the function is impaired, its value is often normal, so it is inevitable that false negatives will occur.
(2) Determination of blood pregnancy-specific 1 glycoprotein (SP1): SP1 is produced by placental syncytiotrophoblast cells. After implantation, the pregnant egg enters the maternal blood circulation, and the content gradually increases to 200mg/L in the third trimester, which is hPL. The concentration is 20 to 30 times, and it disappears rapidly after delivery. It is a good indicator for the detection of placental function. It is usually measured by radioimmunoassay and single-phase immunodiffusion method. It can reach the peak at 38 weeks of pregnancy, and declines after 39 weeks of pregnancy, and is maintained until delivery. Low-value (<80mg/L) patients with fetal distress or high neonatal low Apgar scores have a high diagnostic value for fetal distress.
(3) Maternal meconium index (UMI) measurement: fetal intrauterine hypoxia, meconium discharge into amniotic fluid, meconium-like substances into the mother, discharged from the mother urine, maternal UMI indirectly reflects whether amniotic fluid mixed with meconium It can quickly find a simple and rapid method for measuring fetal hypoxia. The clinical criteria are: UMI optical density <0.5 prompts normal, 0.5-0.99 suspected fetal distress, UMI1 indicates fetal risk.
(4) Comprehensive score of laboratory monitoring: In recent years, the above four measurements were comprehensively scored to improve the accuracy of diagnosis of fetal recessive distress. Specific methods: parental E3/C ratio, maternal UMI (light) Density), maternal blood hPL (mg / L), SP1 (mg / L) of the normal value is set to 2 points, 1 is suspicious, 0 is divided into danger, the results of various monitoring results.
4. Fetal heart monitoring
Since the first report of the fetus in the 1960s, Hen et al. (fetal electronic mornitoring, or cardiatocography, CTG) has been widely used in clinical practice. It can continuously record and observe changes in fetal heart rate, as well as uterine contractions, fetal movements, etc. The influence of fetal heart rate and the formation of a complete set of fetal heart rate map analysis methods, fetal heart monitoring methods have two methods of internal monitoring and external monitoring, internal monitoring refers to pregnant women, after the opening of the palace mouth 2cm, Artificially rupture the membrane, place the electrode on the scalp of the fetus, record the fetal heart rate according to the fetal ECG changes, and place the uterine pressure probe in the amniotic cavity to directly detect the uterine pressure. This method is more accurate, but because it is Interventional, invasive detection methods, may cause infection and injury, clinically not commonly used, external monitoring is the application of Doppler principle in the detection of fetal heart rate in the abdominal wall of pregnant women, and indirect reflection of uterine cavity pressure according to changes in abdominal wall pressure The fetal heart rate detected by the method has a certain error, but the error is within the allowable range, and is convenient, simple, and repeatable. Wide.
The indicators related to fetal distress in the fetal heart rate monitoring map are: early deceleration (ED), late deceleration (LD), variable deceleration, fetal heart rate baseline variability decreased or disappeared, after fetal movement Accelerated fetal heart rate, persistent fetal tachycardia or bradycardia, and rare sinosoid pattern, prolonged bradycardia and other manifestations reflect the possibility of fetal distress.
The analysis methods of fetal heart rate monitoring during pregnancy and childbirth are different. The fetal heart rate monitoring during pregnancy without obvious contractions is called non-stress test (NST). After 20 minutes of observation, there are 2 fetal movements. Accelerated fetal heart rate, duration of acceleration >15s, amplitude >15 beats/min (bepms per minute, bpm); fetal heart rate and fetal heart rate variability are in the normal range; no fetal heart rate deceleration It is called NST, otherwise it is non-responsive. The conditional unit takes NST as a routine examination in the third trimester of pregnancy. The fetal heart rate monitoring time starts at 32-35 weeks of pregnancy. High-risk pregnancy can be monitored in advance.
Fetal heart monitoring during childbirth includes the contraction stimulate test (CST) and the oxytocin ehallenge test (OCT). The CST and 0CT tests require that the contractions should be more than 3 times within 10 minutes. When the late deceleration or atypical variability is decelerated, it is called CST or OCT positive, which is the manifestation of fetal distress. The fetal heart monitoring during childbirth has attracted more and more people's attention. It is widely used as a routine and indispensable means. In clinical practice, this article focuses on the admission test (AT).
In low-risk pregnancies, in order to comprehensively assess the status of the intrauterine fetus, it is predicted that there may be conditions during childbirth. Pregnant women undergo fetal heart rate monitoring at the time of admission. This test is called a laboratory test. The laboratory test can quickly find that general auscultation cannot Fetal abnormalities found, even in the absence of contractions or weak contractions in early labor, the laboratory test can find obvious fetal abnormalities. In 1986, Ingemasson et al reported the results of 1041 cases of hospitalization, pregnant women were admitted to the hospital for 20 minutes. Electronic monitoring, when the fetal heart rate and fetal heart rate variability are in the normal range, there are more than 2 fetal heart rate acceleration (duration > 15s, increase range > 15 times / min), and no fetal heart rate is considered when there is no deceleration The guardianship is normal, and when one of the abnormalities is called suspicious.
When there are more than two abnormalities or late deceleration, it is called obvious abnormality. When the fetal heart monitoring abnormality requires cesarean section or forceps assisted delivery, or the delivery is accompanied by 5 minutes postpartum, the Apgar score is diagnosed as fetal distress when the score is below 7 points. RESULTS: Of the 1041 cases, 982 were normal, 13 of them (1.4%) had fetal distress; 49 patients were suspicious, including 5 cases of fetal distress (10.0%); 10 cases of abnormal hospitalization, including 4 cases of fetal distress (40) %), the results showed that the hospitalization test is very important in predicting fetal distress during childbirth. Further analysis of 13 cases of normal femoral distress, but 10 cases of fetal distress occurred 5 hours after the laboratory test, and 3 cases occurred. Within 5 hours of the entrance test, 1 case was umbilical cord prolapse, and 2 cases were premature infants with gestational age <35 weeks. When the fetal development was normal, the ventricular test was normal, and there was no risk factor, it took 115 minutes to develop into a late deceleration during childbirth. It takes 145 minutes for the development to slow down the variability, and 185 minutes for the fetal heart rate variability to disappear. Therefore, the ventricular test is performed in the low-risk pregnancy, and the method for further fetal monitoring is determined according to this. Feasible and safe.
In the second stage of labor, it is difficult to diagnose fetal distress according to fetal heart monitoring. Because the fetal head reaches the pelvic floor in the second stage of labor, the degree of pressure on the fetal head is heavier, and about one third of the fetus has a deceleration of fetal heart rate; However, not all fetuses with abnormal fetal heart rate have fetal distress. Many medical units use fetal heart rate continuous monitoring in the second stage of labor. When the fetal heart rate decelerates and the following conditions are met, consider ending the delivery:
(1) Fetal heart rate variability is poor.
(2) Base rate of fetal heart rate > 160 beats / min, or < 120 beats / min.
(3) The fetal heart rate deceleration is late deceleration or delayed deceleration (duration 2 min).
(4) The fetal heart rate during the uterine contraction period cannot be restored to the normal range.
With the wide application of fetal monitoring, the insufficiency and shortcomings of fetal heart monitoring have also attracted people's attention. First of all, there are many factors affecting fetal monitoring results. The false positive rate of fetal heart monitoring for fetal distress is very high, leading to global cross-section. The yield of the palace is increased.
In the past 10 years, research on fetal heart monitoring has been developed, mainly reflected in the hardware and map analysis software of the instrument, the development of computers and networks, the development of fetal monitoring in the direction of networking and remoteness, and the monitoring of fetal heart rate. Analysis of the development of computer experts and other systems can avoid the subjectivity of analysis.
5. Biophysiologic proffle scores (BPPs)
(1) BPPs scoring methods: BPPs include fetal heart monitoring, fetal movement (Fetal movment, FM), fetal respiratory movement (FBM), fetal muscle tension (Fetal toning, FT), amniotic fluid volume (Amnio fluid volumne , AFV), and placental grading (Plecenta, PL), fetal BPPs scoring methods are many, currently the most widely used methods such as Manning et al and ventzeil, Manning's method only includes the first 5 indicators, each 2 points, a total of At 10 points (Table 2), Ventzeil's scoring method included all six indicators, each with 2 points, a total of 12 points. Later, many improved methods appeared, but none of them exceeded the six indicators.
(2) Precautions for BPPs application
1Because of the physiological sleep cycle of the fetus, the fetal movement decreases during sleep, and the variability of the baseline decreases. Therefore, the 20-minute monitoring of BPPs often has false positive results. In order to reduce the impact of fetal sleep cycle on BPP or CTG, many scholars have proposed Give external stimulation such as fetal sounds or extend the examination time to improve the fetus's reactivity.
2 various biophysical indicators of the fetus: there is a certain order in the development of the fetus, followed by FT, FM, FBM and fetal heart rate responsiveness, FT appears first, about 12 weeks of gestation; fetal heart rate responsiveness appears at the latest About 28 weeks of gestation, and the later the indicator is more sensitive to hypoxia, the order of sensitivity from high to low is (CTG, FBM, FM, FT). This phenomenon is called progressive deficiency. Oxygen theory, according to this theory we should pay attention to 2 points: First, BPPs are adapted to fetal monitoring in the third trimester of pregnancy (generally starting after 32 weeks of gestation); secondly, when FM and FBM are normal and FT is abnormal, the possibility of false positives should be suspected.
The three indicators of 3CTG, FBM, FM and FT are indicators of acute hypoxia in the fetus. AFV is an indicator of chronic hypoxia in the fetus. When only AFV is abnormal and other indicators are normal, BPPs are also in the normal range, but it does not indicate the fetus. Safety should be handled in a timely manner.
4 The application of any kind of examination method should be combined with the clinical specific situation, comprehensive analysis, BPPs are no exception.
6. Fetal Doppler blood flow monitoring
Color Doppler ultrasound can not only detect the Doppler index of umbilical artery and pregnant uterine artery, but also detect the indicators of fetal blood vessels (such as renal artery, middle cerebral artery, etc.). Doppler ultrasonography is very important in pregnancy-induced hypertension. The meaning.
Umbilical artery (umbilical arlery, umA) S / D 3.0, PI 1.7 or RI 0.7 indicates abnormality, umA Doppler index abnormalities reflect fetal-placental circulation resistance, maternal and child exchange dysfunction; suggesting fetal poor prognosis .
The fetal renal artery (RA) PI2.5 indicates abnormality, which reflects the increase of fetal renal artery resistance, and is related to fetal distress, fetal urinary system malformation, and oligohydramnios.
The fetal cerebram anesthesia (MCA) PI<1.45 indicates abnormality, reflecting the compensatory expansion of cerebral blood vessels during fetal distress, but our data show that the PI of MCA has an increasing trend during pregnancy-induced hypertension. Fetal distress occurred in pregnant women, and the PI of MCA did not change significantly.
7. Fetal ECG
FECG can be divided into transabdominal wall and transvaginal 2 types. Due to the long distance, the interference of maternal electrocardiogram, the signal of FACG through the abdominal wall is unstable, the extraction is difficult; transvaginal FECG is a traumatic test, there are concerns about intrauterine infection, due to Its own defects, the application of FECG is not very extensive.
8. Fetal scalp blood gas analysis
The pH of fetal arterial blood and blood gas analysis The pH and blood gas analysis of fetal arterial blood is a more accurate method for judging fetal distress. In many clinical studies, it is the gold standard for fetal distress. When the fetus is hypoxic, the anaerobic glycolysis in the body is enhanced. Acidic metabolites accumulate, when the buffer balance is decompensated and disorder occurs, the pH value in the blood can be decreased, and the degree of hypoxia is positively correlated with the change of pH value. The pH of the fetal scalp blood is 7.25 to 7.30, and the pH is 7.20~ 7.25 is suspected hypoxia, pH <7.20 should be diagnosed fetal hypoxia, timely termination of pregnancy, combined with fetal heart rate monitoring and fetal scalp blood pH, can improve the accuracy of the diagnosis, but one test can not estimate the prognosis, must be repeated many times Carry out, but this is a destructive means, clinical application has certain indications and skilled operation level, so it is difficult to clinically promote and apply.
9. Near-infrared spectroscopic analysis
Wyatt et al. applied the near-infrared spectroscopy (700-1000 nm) to the permeability of biological tissues, thereby obtaining the spectroscopic spectrum of brain tissue without damage, and obtaining the indicators of cerebral oxygen content and hemodynamics according to the spectrum, and Peebles et al. The technique measures fetal brain hemoglobin concentration and oxygen content after labor, and found that oxyhemoglobin and deoxyhemoglobin are related to the absorption of near-infrared light waves with wavelengths of 775 nm and 908 nm, respectively, and after rupture of the cervix to 3-6 cm, A fiber beam is placed on both sides of the fetal head at the cervix, and the fiber beams are respectively connected to the spectrometer, and the hemorrhage oxygen saturation is calculated according to the absorption rate of light waves having wavelengths of 775 nm and 908 nm.
Diagnosis
Diagnosis of fetal distress
diagnosis
1. Diagnosis of chronic fetal distress
(1) placental function test: determine the 24-hour urine E3 value and observe continuously, if the acute aggregation is reduced by 30% to 40%, or in the end of pregnancy, the 24-hour urine E3 value is below 10mg, indicating fetal placental function. Decrease.
(2) Fetal heart monitoring: Continuously describe the fetal heart rate of pregnant women for 20 to 40 minutes, and the normal fetal heart rate baseline is 120 to 160 beats/min. If the fetal heart rate is not accelerated at the time of fetal movement, the baseline variability is <3 times/min, suggesting fetal distress.
(3) Fetal movement count: When the pregnancy is near full term, the fetal movement is >20 times/24 hours. The calculation method can detect the number of fetal movements for each hour in the early, middle and late pregnancy, and multiply the number of fetal movements by 3 times, which is the number of fetal movements close to 12 hours. Fetal movement reduction is an important indicator of fetal distress, and daily monitoring of fetal movement can predict the safety of the fetus. After the fetal movement disappears, the fetal heart will disappear within 24 hours, so you should pay attention to this point so as not to delay the rescue opportunity. Excessive fetal movement is often a precursor to the disappearance of fetal movement, and should also be taken seriously.
(4) amniocentesis: see amniotic fluid turbid yellow stained to dark brown, which helps the diagnosis of fetal distress.
2. Diagnosis of acute fetal distress
(1) fetal heart rate change: fetal heart rate is an important sign to understand whether the fetus is normal: 1 fetal heart rate > 160 beats / min, especially > 180 beats / min, for the initial performance of fetal hypoxia (pregnant heart rate is not fast 2 cases of fetal heart rate <120 beats / min, especially > 100 beats / min, for fetal risk; 3 late fetal heart rate deceleration, variability deceleration or (and) baseline lack of variation, all indicate fetal distress. When the fetal heart rate is abnormal, the cause should be examined in detail. Fetal heart rate changes can not be determined by only one auscultation. Multiple examinations should be performed and the position should be changed to the lateral position for a few minutes.
(2) Amniotic fluid meconium contamination: fetal hypoxia, causing vagus nerve excitement, intestinal peristalsis, anal sphincter relaxation, so that meconium is discharged into amniotic fluid, amniotic fluid is green, yellow-green, and then turbid brownish yellow, that is, amniotic fluid I Degree, II degree, III degree pollution. After the membrane is broken, the amniotic fluid flows out, and the characteristics of the amniotic fluid can be directly observed. If the membrane is not ruptured, it can be seen through the amniotic membrane and through the membrane to understand the characteristics of amniotic fluid. If the first exposed part of the tire is fixed, the former sheep's water sac can reflect the difference between the amniotic fluid and the amniotic fluid. If the anterior amniotic fluid sac is clear and the fetal heart rate is not normal, if the rupture of the membrane can be broken according to the situation, the scallops can be slightly lifted up after disinfection. The amniotic fluid above it can understand the water content of the lower part of the amniotic cavity. .
Amniotic fluid I degree, even II degree pollution, fetal heart rate is always good, should continue to closely monitor fetal heart rate, not necessarily fetal distress, amniotic fluid III degree polluters, should end early delivery, even if the newborn Apgar score may be 7 points It should also be vigilant because of the high chance of newborns. Mild contamination of amniotic fluid, abnormal monitoring of fetal heart after about 10 minutes of monitoring, should still be diagnosed as fetal distress.
(3) Fetal movement: In the early stage of acute fetal distress, the first manifestation is fetal movement frequency, and then weakened and the number of times decreased, and then disappeared.
(4) Acidosis: After rupture of the membrane, the fetal scalp blood is examined for blood gas analysis. The indicators for diagnosing fetal distress are blood pH < 7.20, PO2 < 1.3 kPa (10 mm Hg), and PCO 2 > 8.0 kPa (60 mm Hg).
Mainly based on fetal monitoring, amniotic fluid fecal pollution to determine the degree of fetal hypoxia, to determine the treatment method to take measures to make mother and child safe.
Clinical diagnosis of fetal distress should be based on hospital conditions using a variety of methods to jointly monitor, to improve the clinical diagnosis of the coincidence rate, to exclude false positive and false negatives of the single monitoring method, for the monitoring of high-risk pregnant women during pregnancy, you can first teach pregnant women Fetal movement, when the pregnant woman feels less fetal movement or the fetal heart rate changes, timely fetal heart monitoring, when the fetal heart monitoring shows obvious signs of fetal distress, it should be clearly diagnosed in time, when the fetal heart monitoring performance is suspicious fetal distress, can be further B-ultrasound biophysical score can also be artificially ruptured according to gestational age, maturity of the fetus, cervical conditions, etc., to understand the condition of amniotic fluid, when fetal heart rate monitoring, biophysical indicators and amniotic fluid are all poor, the possibility of fetal distress Sexually increased, should consider the timely termination of pregnancy, fetal heart rate abnormality during childbirth, such as abnormal CST or amniotic fluid turbidity, should be taken dynamically dynamic monitoring of fetal heart rate, conditional hospital feasible fetal scalp blood pH check or oxygen saturation Degree monitoring, if not corrected in time, should terminate the pregnancy immediately.
