Nuchal cord entanglement

　　Umbilical cord around the neck is mainly related to the umbilical cord being too long, the fetus being too small, there being too much amniotic fluid, and fetal movements being too frequent:

　　1. The fetus is not quiet in the mother's womb, it rolls and twists in the relatively small uterus, often active. Each baby has different characteristics, some babies have gentle movements, and some have larger movements and especially love to move. It plays and moves in the mother's womb, moves its arms and legs, and even turns around, and at this time, it may cause umbilical cord wrapping.

　　2. Umbilical cord wrapping is related to the umbilical cord being too long, fetal movements being too frequent. In the middle of pregnancy, the uterine cavity is large, while the fetus is relatively small, and they have a large range of movement. If the umbilical cord is too long or the fetus is undergoing a large-scale activity from the vertex position to the breech position or from the breech position to the vertex position, it is possible to have umbilical cord wrapping.

　　3. For the fetus wrapped around once by the umbilical cord or the fetus with the umbilical cord over the neck, due to the lighter wrapping and compression, no clinical symptoms will occur. This kind of wrapping is not very dangerous to the mother and child, and the mother can still deliver the baby smoothly through the vagina. Even if the umbilical cord wraps around the neck, due to the smaller mobility of the fetal head, as long as the umbilical cord is not tightly tied, it usually will not harm the health of the fetus.

　　4. For the fetus with a large number of wraps and severe compression, due to the umbilical cord wrapping, it can lead to relatively short umbilical cord, and the tighter the wrapping, the more it affects the blood flow of the umbilical cord, which will first affect the metabolism of oxygen and carbon dioxide in the fetus, causing the fetal heart rate to slow down. In severe cases, it may lead to fetal hypoxia, even fetal death, so it should be paid special attention.

　　Umbilical cord around the neck is a high-risk pregnancy that can cause fetal distress in the womb at any time. In the late pregnancy, if the umbilical cord is wrapped in multiple places, it is very dangerous for the fetus. The tighter the wrapping, the more it can affect the blood flow of the umbilical cord, thus affecting the metabolism of oxygen and carbon dioxide in the fetus, causing the fetal heart rate to slow down. In severe cases, it may lead to fetal hypoxia, even fetal death. So, what are the complications of umbilical cord around the neck?

　　1. The fetus is in distress;

　　2. The newborn baby has asphyxia;

　　3. The fetus's growth is limited;

　　4. The umbilical cord is knotted.

　　It is easy to have the umbilical cord wrap around the neck when the umbilical cord is too long, the fetus is too small, there is too much amniotic fluid, and the fetal movements are too frequent. The typical symptoms of umbilical cord around the neck include:

　　1. The fetal movements are too frequent or significantly reduced;

　　2. There is too much amniotic fluid;

　　3. The umbilical cord is too long;

　　4. Frequent changes in fetal position.

　　The umbilical cord is the only channel of mutual connection between the mother and the fetus. One end is connected to the umbilical ring on the fetal abdominal wall, and the other end is attached to the placenta. The fetus floats in the amniotic fluid with the help of the umbilical cord, exchanges blood circulation with the mother, obtaining oxygen and various nutrients needed from the mother, and at the same time, excreting waste products from the fetus. The development of the umbilical cord, whether good or bad, and whether there are any abnormalities, plays an extremely important role in the healthy development of the fetus. So, how can we prevent the umbilical cord from wrapping around the neck?

　　1. Pregnant women should learn to count fetal movements and go to the hospital for examination in a timely manner if there are too many or too few fetal movements;

　　2. Good prenatal examination should be done for excessive or insufficient amniotic fluid and malpresentation;

　　3. Through indirect methods such as fetal heart monitoring and ultrasonic examination, the condition of the umbilical cord is judged;

　　4. Pay attention to reducing vibration and maintaining left lateral sleeping position;

　　5. Cesarean section is required when the umbilical cord has an accident.

　　Ultrasonography is the only method for diagnosing umbilical cord around the neck, but the accuracy of ultrasonic diagnosis is not completely reliable. Even experienced ultrasonographers may misdiagnose or miss the diagnosis of umbilical cord around the neck. Doppler ultrasonography can provide hemodynamic information of umbilical blood vessels, including blood flow velocity, resistance index, pulsatility index, and other parameters, providing a strong basis for judging whether the fetus with umbilical cord around the neck is suffering from intrauterine distress.

　　First, scanning technique

　　When the ultrasonic examination is suspicious of umbilical cord wrapping at this location, the probe should be scanned along the fetal longitudinal axis and rotated to both sides, sliding the probe as much as possible in an arc shape with this location as the axis, and the probe is horizontally placed at this location for upper and lower compensation scanning.

　　Second, ultrasonic manifestations

　　There is a concave mark on the fetal body surface at this location. It is 'U' shaped for 1 week, 'W' shaped for 2 weeks, and can be arranged in parallel or overlapped and crisscrossed for more than 2 weeks. The skin concave mark has different manifestations. The umbilical cord extends to the opposite side behind this part. When it is confirmed that the umbilical cord is wrapped, if the umbilical cord is floating and has a distance from the fetal body surface at this part, and there are echo signals of twisted and floating umbilical cords in other parts, it indicates that the wrapping is loose. If the umbilical cord is tightly adhered to the wrapping part, it is difficult to detect the umbilical cord echo in the amniotic fluid, or the umbilical cord is in a straight traction state, it should be considered as too tight wrapping or too short umbilical cord. The following are the precautions for ultrasonic diagnosis of umbilical cord around the neck:

　　1. The time for ultrasonic diagnosis of umbilical cord around the neck should be chosen before delivery. The closer to delivery, the more reliable the results are (accuracy rate 97%). Before 30 weeks of gestation, the umbilical cord wrapped around the fetus due to fetal movement can be released or re-wrapped spontaneously (accuracy rate 80%).

　　2. If the signs of umbilical cord around the neck are accompanied by fetal bradycardia or irregular heartbeat, it indicates fetal distress and emergency measures should be taken in a timely manner.

　　3. During the examination, the long axis section of the fetal neck and back should be displayed as clearly as possible. The range of the transverse scan of the neck should include both sides and the lateral side of the neck as much as possible, to find whether there is an umbilical cord crossing.

　　4. The probe should not be pressed heavily on the abdominal wall during scanning to avoid the compression of amniotic fluid around the fetal neck, which may reduce the diagnosis.

　　5. The U-shaped indentation of the neck should be distinguished from the V-shaped skin creases formed at the neck and shoulder junction of a slightly overweight fetus, and attention should be paid to near-field accumulation and the interference of false images.

　　6. The simple appearance of U-shaped indentation and color Doppler flow in the neck and back is not sufficient to confirm the diagnosis. It must be accompanied by color Doppler flow or W-shaped indentation on the fetal lateral side to be confirmed. Because the umbilical cord can be wrapped around the cheeks, orbit in front of the eyes, and shoulders, not around the neck.

　　7. When the pregnant woman's lying position examination is difficult to distinguish umbilical cord around the neck due to less amniotic fluid, the standing position scan can be used instead, using gravity to accumulate amniotic fluid below the amniotic cavity, forming a transparent window.

　　Pregnant women with nuchal cord should eat small and frequent meals, have a light diet, and eat blood-nourishing foods and supplement sufficient high-quality protein. Eat more nutritious foods, avoid smoking and drinking, and foods that are too spicy or strongly刺激性, and avoid raw seafood, unripe, and easily allergic foods.

　　If the umbilical cord of the fetus is too long (the length of the umbilical cord exceeds 70 centimeters), it is not a problem if the umbilical cord wraps around the neck for 1-2 weeks; but some fetuses have too short umbilical cords (the length of the umbilical cord is less than 30 centimeters), even if it does not wrap around the neck, it will be dangerous when the fetal head descends during labor. Regular prenatal examinations should be scheduled, and close monitoring should be conducted. Once abnormal fetal movements occur, appropriate countermeasures should be taken.

　　1. Routine Monitoring

　　The monitoring of nuchal cord and normal prenatal monitoring are consistent, and there is no need to cause excessive panic. Pregnant women also need regular prenatal examinations, learn to count fetal movements, and go to the hospital for a check-up in case of excessive or insufficient fetal movements. It is not recommended to commonly listen to fetal heart sounds during pregnancy, because the normal or abnormal variation of fetal heart sounds requires professional analysis, and self-listening to fetal heart sounds often leads to too many misunderstandings, psychological anxiety, and unnecessary interventions.

　　2. Mode of Delivery

　　Nuchal cord is not an indication for cesarean section. Because the incidence of nuchal cord is very high, it does not mean pathological condition. Strengthening the monitoring during labor will not increase the morbidity rate of the fetus/newborn with nuchal cord. Prenatal examination can be used to diagnose whether there is a nuchal cord mark on the fetus's body through B-ultrasound, and check whether the wrapping affects the health of the fetus. Fetal heart rate changes can be observed through fetal electronic monitoring. If there is irregular deceleration or a large variation in fetal heart rate, it should be considered that the umbilical cord is being pulled or compressed. The treatment of nuchal cord mainly depends on the progress of labor and the degree of impact on the fetus. If the fetus shows signs of hypoxia at the beginning of labor, an immediate cesarean section should be performed. If abnormalities are found during the second stage of labor, the fetus should be delivered as soon as possible. If the umbilical cord is found to be too tight during delivery, it should be clamped and cut immediately.

　　3. Other Progress

　　The resistance indicators of the fetal middle cerebral artery (MCA) and umbilical artery (UA) in the fetus with nuchal cord around the neck are measured to be superior to the resistance indicators of the fetus with nuchal cord around the neck, which can early detect the intrauterine hypoxia state of the fetus with nuchal cord around the neck, make a diagnosis before the occurrence of fetal distress, and has important clinical value.