Fetal distress

Introduction The fetus has signs of hypoxia in the uterus, endangering the health and life of the fetus, known as fetal distress. Fetal distress is a syndrome that is one of the main indications for current cesarean delivery. Fetal distress occurs mainly during the labor process and can also occur in the second trimester. Occurrence in the process of labor, can be the continuation and aggravation of the late pregnancy. It is divided into acute hypoxia and chronic hypoxia. Acute hypoxia is more common in the time of birth. Chronic hypoxia is common in pregnancy complications and complications affecting placental function.

Cause

1. Maternal factors Insufficient oxygen in the maternal blood is an important cause. In mild hypoxia, the mother has no obvious symptoms, but it has an effect on the fetus. The maternal factors that cause fetal hypoxia are:

(1) Insufficient blood supply to small arteries: such as hypertension, chronic nephritis and pregnancy-induced hypertension.

(2) Insufficient oxygen carrying capacity of red blood cells: such as severe anemia, heart disease, heart failure and pulmonary heart disease.

(3) Acute blood loss: such as prenatal bleeding disorders and trauma.

(4) uterus placental blood supply obstruction: emergency or uterine inconsistent contraction; improper use of oxytocin, causing excessive contractions; prolonged labor, especially the second stage of labor extension; excessive uterine expansion, such as polyhydramnios and multiple births Pregnancy; premature rupture of membranes, umbilical cord may be stressed.

2. Fetal factors

(1) Fetal cardiovascular system dysfunction, such as intracranial hemorrhage of severe congenital cardiovascular disease.

(2) Fetal malformation.

3. Umbilical cord, placenta factor The umbilical cord and placenta are the transmission and transmission channels of oxygen and nutrients between the mother and the fetus. The dysfunction will inevitably affect the fetus's inability to obtain the required oxygen and nutrients.

(1) Cord blood supply is blocked.

(2) Low placental function: such as expired pregnancy, placental development disorder (too small or too large), abnormal placental shape (membranous placenta, contoured placenta, etc.) and placental infection.

an examination

Related inspection

Fetal heart monitoring obstetrics B-ultrasound blood flow examination fetal biophysical phase score

Fetal movement monitoring

It indicates that the fetal movement is reduced, especially when the fetal movement is less than 4 times/hour, it is necessary to pay attention to the possibility of fetal death.

2.B type ultrasound system examination

Fetal biparietal diameter, head and abdomen circumference ratio, femur length, amniotic fluid volume, etc. indicate fetal growth retardation.

3. Fetal heart monitoring has prenatal stress-free test (nst)

When the fetal movement is observed, there is no accelerated reaction, or no fetal movement, which means no reaction. Sometimes the fetal heart rate spontaneously decelerates. The contraction stress test (cst) can be a positive result.

4. Comprehensive biophysical image score check

That is, the B-type ultrasound measurement of fetal respiration, fetal movement, fetal tension, amniotic fluid volume, nst test by fetal monitoring, can be expressed as a low score.

5. Placental function check

The ratio of estriol, placental lactogen, and estrogen/creatinine can be measured, with a continuous low or decreasing trend.

6. Amniocentesis

See amniotic fluid for meconium contamination.

Differential diagnosis

1. Chronic fetal distress occurs mostly in the end of pregnancy, often extending to labor and aggravating. 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 hypotension, shock, etc. cause. Clinical manifestations in fetal heart rate changes, amniotic fluid meconium contamination, fetal movement frequency, fetal movement disappeared and acidosis.

an examination

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 pollution: 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 neonatal asphyxia. 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).

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