Dystocia

　　Dystocia refers to the condition where the opening period (the first stage) of childbirth, especially the expulsion period (the second stage), is significantly prolonged due to various reasons, making it difficult or impossible for the mother to deliver the fetus without artificial assistance, which is an obstetric disease. If not properly managed, dystocia can not only cause reproductive tract diseases in the mother, affecting her future fertility, but may also threaten the lives of both the mother and the fetus. Dystocia is generally caused by the following factors:

　　1, Force of Labor

　　The force that expels the fetus and its附属物 from the uterus is called the force of labor, which is the uterine contraction force we often talk about. After the cervix is fully dilated, the contraction force of the abdominal wall muscles and diaphragm (the force of abdominal pressure) and the contraction force of the levator ani muscle form the force of labor, of which the uterine contraction force is the most important factor. If the force of labor is insufficient, it can lead to difficult labor.

　　2, Birth Canal

　　The birth canal is the passage through which the fetus is delivered, and it is divided into the bony birth canal and the soft birth canal. The 'pelvis' we usually refer to is the bony birth canal. The size, shape, and relationship with delivery are closely related. The main cause of difficult labor is the mismatch between the pelvis and the fetus due to the fetus being too large or the fetal head being in an abnormal position, which is briefly referred to in medicine as 'dysmorphism'. This leads to difficult labor.

　　3, Fetus

　　The fetus is another key factor in determining whether a difficult labor will occur, which depends on the size of the fetus, the position of the fetus, and whether there are any malformations. A fetus weighing more than 4000 grams is considered a macrosomic fetus. During the delivery process, if the fetus is large and the fetal head circumference is large, even if the pelvis is measured normally, it can still lead to difficult labor due to the mismatch between the fetal head and the pelvis, causing relative pelvic narrowness. Some fetuses are not very heavy, but an abnormal position of the fetal head can also lead to difficult labor. Clinically, it is often seen that the fetal head cannot descend into the pelvis near the expected delivery date or during labor, and remains in a floating fetal head state. In such cases, it is important to be vigilant about the mismatch between the fetal head and the pelvis, which can lead to difficult labor.

　　4, Psychological

　　We must recognize that factors affecting delivery include not only the mother's strength, birth canal, and fetus, but also the psychological and mental factors of the expectant mother. The vast majority of first-time deliveries are a long process of labor pain. Severe pain, the unfamiliar and isolated environment of the delivery room, and other factors can increase the fear and anxiety of the expectant mother, leading to abnormal labor.

　　Difficult labor can lead to meconium aspiration syndrome. The amniotic fluid ingested by the fetus contains some shed cells, fetal hair, fetal fat, and other impurities. As the fetus approaches full term, these impurities accumulate in the intestines to form a thick, dark brown-green substance known as meconium. Babies usually pass meconium after birth. If the fetus experiences oxygen deficiency or distress in the uterus, stimulating the vagus nerve can cause the anal sphincter to relax, leading to the early expulsion of meconium and contamination of amniotic fluid. Early meconium is more likely to occur in high-risk pregnancies such as prolonged pregnancy, intrauterine growth restriction, oligohydramnios, and prolonged labor. However, prenatal ultrasound cannot distinguish whether meconium is present in amniotic fluid, and it is only discovered when the water breaks. Continuous fetal heart rate monitoring can ensure the health of the fetus during the subsequent labor process. During delivery, it is important to summon a pediatrician to be present. Once the fetal head is delivered, it should be immediately suctioned to remove foreign matter from the mouth and nose. After the body is delivered, it should also be suctioned clean as soon as possible, and it is important not to hurry the baby to cry loudly. However, since the fetus has obvious breathing movements in the uterus, some meconium may already be present in the trachea, and it is inevitable that there is a possibility of aspiration into the lungs, leading to respiratory distress. After birth, it is up to the pediatrician to provide active monitoring and treatment, with a good prognosis almost always expected.

　　In a normal delivery process, after the fetal head is delivered, the body follows. Once it is found that the fetus's shoulders are stuck in the outlet of the birth canal, the perineal incision is immediately enlarged, the mother's legs are raised, the uterus is strongly pushed, and the fetus's shoulders are rotated back and forth. If the fetus still cannot be delivered, it is necessary to break the fetus's clavicle. Generally speaking, shoulder dystocia often leads to neonatal brachial plexus injury or clavicle fracture, and if it lasts for more than a few minutes, it may lead to death due to asphyxia caused by umbilical cord compression.

　　Shoulder dystocia usually occurs without any warning. Theoretically, the higher the fetal weight, the higher the chance of the shoulders getting stuck, so some people advocate that if the ultrasound estimation of fetal weight is too high before birth, it should be considered to undergo cesarean section directly. However, regardless of the 10% or so error in ultrasound measurement, about half of the shoulder dystocia cases occur in babies weighing less than 4000 grams.

　　In the process of labor, any stage that does not go smoothly can lead to a prolonged labor time and can be called dystocia. From the stage of labor pain to the full dilation of the cervix, if it is below twelve hours, it is considered normal. Many mothers are giving birth for the first time, and we call them primiparas. If primiparas exceed twenty hours, it is considered dystocia; if multiparas (women who have given birth before) exceed fourteen hours, it is also considered dystocia. From the stage of full dilation of the cervix to the birth of the fetus, within two hours is considered normal delivery; over two hours is dystocia. From the birth of the baby to the delivery of the placenta, five to thirty minutes is considered normal; over 30 minutes is dystocia.

　　1. Narrow pelvis outlet of the mother.

　　2. Abnormal fetal position or abnormal presentation: Due to the widespread use of prenatal ultrasound, abnormal fetal positions (such as breech or transverse) are usually detected; abnormal presentation (such as the fetus's posterior occiput being in the exact posterior position) generally needs to be discovered during the labor process through internal examination.

　　3. Fetal macrosomia: Fetal macrosomia is actually relative to pelvic inlet stenosis. Mothers with wider pelvises can deliver larger infants vaginally. In some special situations, fetal macrosomia is more likely to occur, such as mothers with diabetes or gestational diabetes, or those who had a macrosomic baby in their previous pregnancy.

　　In fact, even if the ultrasound estimation of fetal weight is accurate, it is difficult to predict shoulder dystocia caused by particularly thick shoulders of the fetus solely based on the estimated weight size, because the birth weight of such a fetus is not necessarily very heavy.

　　4. Fetal abnormalities: If a fetus has congenital tumors such as spinal cord tumors, teratomas, fetal hydrocephalus, conjoined twins, etc., they can generally be diagnosed by ultrasound before birth.

　　To prevent dystocia, it is necessary to undergo prenatal examinations at regular hospitals, and pelvic measurements should be done in the late stages of pregnancy to enable doctors to have a comprehensive understanding of the mother and baby's condition. Generally, about two weeks before the expected delivery date, doctors will make a determination of the mode of delivery and inform the mother in advance, so that she knows whether she can deliver naturally or needs a trial delivery. If cesarean section is the only option, she will also be informed to prepare herself mentally and physically.

　　(1) Regular prenatal examination

　　The role of prenatal examination is to check for diseases related to the mother on one hand, and to check whether the fetus is developing normally on the other hand. It can effectively monitor the entire pregnancy, so it is still very necessary. For example, malpresentation is an important cause of dystocia, and it can be detected early through prenatal examination. As long as the pregnant woman follows the doctor's advice and actively cooperates in adjusting the fetal position, she can usually have a normal delivery. If the prenatal examination is not done during pregnancy, and the malpresentation is discovered only at the time of labor, it is very harmful to the smooth progress of delivery and the health of both the mother and the fetus. Therefore, pregnant women should have regular prenatal examinations and solve problems early.

　　(2) Balanced nutrition

　　A large fetus is now the main cause of dystocia. With the improvement of people's living standards and the fact that most are only children, families treat them as treasures. As a result, they try to supplement the pregnant woman's nutrition, leading to both the pregnant woman and the fetus becoming overweight, which brings great difficulties to childbirth. Experts point out that during pregnancy, the weight gain of the pregnant woman should be controlled within a reasonable range of 10 to 14 kilograms. If the baby's head is too large (BPD over 10 centimeters), delivery will be difficult, and once BPD exceeds 10.5 centimeters, vaginal delivery will be impossible. Therefore, as long as a balanced diet is maintained during pregnancy, it is enough to ensure the necessary nutrients for fetal development.

　　(3) Pay attention to exercise, help with delivery

　　Some pregnant women themselves do not like to exercise, or they try not to exercise as much as possible during pregnancy for the safety of the fetus, which is very unwise. Experts remind all pregnant mothers that if their physical condition allows, they should engage in appropriate exercise during pregnancy. Delivery is a quite physically and mentally demanding activity, and pregnant mothers should accumulate energy for a smooth delivery. Some pregnant women do not have enough physical strength to maintain the process during delivery, leading to a long delivery time and causing fetal hypoxia. Therefore, pregnant women should still exercise more during pregnancy, strengthen their cardiovascular and respiratory function and overall physical condition, and lay a solid foundation for a smooth delivery.

　　The examination for dystocia should first inquire about whether the pregnant woman had rickets, poliomyelitis, tuberculosis of the spine and hip joints, and a history of trauma in her childhood. If she is a multipara, she should understand whether she has a history of dystocia and its causes, and whether the newborn has birth injuries.

　　1. General examination

　　Measure height, if the pregnant woman's height is below 145cm, be vigilant of a small pelvis. Pay attention to the pregnant woman's body shape, whether there is a limp, whether there are deformities in the spine and hip joints, whether the Myer's cleft is symmetrical, and whether there are conditions such as a pointed abdomen and a hanging abdomen.

　　2. Abdominal examination

　　(1) Abdominal shape: Pay attention to the abdominal shape, measure the length of the uterus above the pubic symphysis and the abdominal circumference, observe the relationship between the fetal presentation and the pelvis with B-ultrasound, and also measure the biparietal diameter, chest circumference, abdominal circumference, and femur length of the fetal head, predict the fetal weight, and judge whether it can pass through the birth canal smoothly.

　　(2) Abnormal fetal position: Narrowing of the pelvic inlet is often due to malposition of the head and pelvis, making it difficult for the fetal head to enter the pelvis, leading to abnormal fetal position, such as breech presentation and shoulder presentation. Narrowing of the middle pelvis affects the internal rotation of the fetal head that has entered the pelvis, leading to persistent occipito-transverse position and occipito-posterior position, etc.

　　(3) Estimating the relationship between the head and pelvis: Under normal circumstances, some primigravid women should have the fetal head enter the pelvis two weeks before the expected delivery date, and for multiparous women, it should enter the pelvis during labor. If labor has started but the fetal head has not entered the pelvis, a full estimation of the relationship between the head and pelvis should be made. The specific method to check whether the head and pelvis are well-suited is for the pregnant woman to empty her bladder, lie on her back, and extend her legs. The examiner places their hands above the symphysis pubis and pushes the floating fetal head towards the pelvic cavity.

　　If the fetal head is below the symphysis pubis plane, it indicates that the fetal head can enter the pelvis, with the head and pelvis being well-suited, known as a negative sign of the transverse sign. If the fetal head is at the same level as the symphysis pubis, it indicates a可疑 malposition of the head and pelvis, known as a可疑 positive sign of the transverse sign. If the fetal head is above the symphysis pubis plane, it indicates a significant malposition of the head and pelvis, known as a positive sign of the transverse sign. For pregnant women with a positive transverse sign, they should be instructed to take a semi-recumbent position with their legs屈曲, and recheck the transverse sign of the fetal head. If it turns negative, it suggests an abnormal pelvic tilt rather than a malposition of the head and pelvis.

　　Pregnant women should pay attention to adjusting their diet to avoid affecting delivery and even triggering difficult labor.

　　One. Foods that are good for difficult labor

　　1. In the early stage of pregnancy, many pregnant women will have symptoms such as nausea, vomiting, and anorexia. Pregnant women may therefore suffer from insufficient intake and malnutrition. However, this period is when the fetus is in the stage of differentiation and formation of various organs, and the demand for protein and vitamins is high. Therefore, pregnant women at this time need to ensure sufficient intake by adopting a method of eating small and frequent meals. When arranging the diet, attention should be paid to the nutritional quality of the diet, and more foods rich in protein and vitamins should be eaten, such as fish, meat, eggs, dairy products, soy products, fresh fruits, and vegetables.

　　2. In the middle stage of pregnancy, the early pregnancy reactions disappear and appetite increases. This period is the stage when the fetus grows and develops rapidly, especially the development of the brain. The dietary arrangement at this time should not only pay attention to the quality of nutrition but also ensure the quantity of nutrition, and eat to satisfy hunger and nourishment. It is necessary to eat more foods rich in protein, vitamins, and trace elements such as calcium and iron, such as fish, meat, liver, eggs, kelp, shrimp, dried tofu, etc.

　　3. In the late stage of pregnancy, the fetus grows more rapidly. In addition, pregnant women in the late stage of pregnancy also need to reserve enough energy for delivery and breastfeeding. At this time, in addition to ensuring the supplement of nutrients such as protein, vitamins, and sugar, attention should also be paid to the supplement of trace elements such as iron, calcium, and zinc. Pregnant women at this time should pay attention to eating more foods such as pork liver, fish, meat, egg yolks, kelp, nori, dried shrimp, black fungus, dried tofu, and peanuts.

　　Two. Foods to avoid during difficult labor

　　1. Fatty foods. Fatty foods contain a high amount of cholesterol, and excessive cholesterol can deposit in the blood, causing a sharp increase in blood viscosity. Added to this is the effect of pregnancy toxins, which can also raise blood pressure, and in severe cases, lead to hypertension diseases such as cerebral hemorrhage.

　　2. Try to eat less spicy food, such as chili, strong tea, coffee, etc.

　　3. It is not advisable to eat too much salty, sweet, and greasy food;

　　4. Absolutely prohibit drinking and smoking.

　　To handle difficult labor in pregnant women, it is first necessary to understand the fetal position, fetal size, fetal heart rate, the strength of uterine contractions, the degree of cervical dilation, whether the amniotic membrane has been ruptured, and make a comprehensive judgment combined with age, parity, and past delivery history to decide the mode of delivery. The main methods of handling difficult labor in pregnant women are as follows:

　　1. General Treatment

　　During the labor process, the midwife should comfort the mother-to-be, make her spirit relaxed and confident, ensure the intake of nutrition and water, and provide fluid replacement if necessary. It is also necessary to pay attention to the mother's rest, monitor the strength of uterine contractions, frequently listen to the fetal heart sound, and check the descent degree of the presenting part of the fetus.

　　2. Treatment of Middle Pelvic and Pelvic Outlet Plane Narrowness

　　During the labor process, the fetus completes flexion and internal rotation at the middle pelvic plane. If the middle pelvic plane is narrow, the flexion and internal rotation of the fetal head are obstructed, and it is easy to occur persistent occipito-transverse position or occiput posterior position. If the cervix is fully dilated and the biparietal diameter of the fetal head reaches the level of the ischial spines or lower, it can be delivered vaginally with assistance. If the biparietal diameter of the fetal head has not reached the level of the ischial spines, or fetal distress signs appear, cesarean section should be performed to end labor.

　　3. Treatment of Pelvic Inlet Plane Narrowness

　　The pelvic inlet plane is narrow, mainly for women with flat pelvis. At the end of pregnancy or during labor, the fetal sagittal suture can only be connected to the transverse diameter of the inlet. The fetal head is laterally flexed to allow the two parietal bones to enter the pelvis successively, presenting an uneven oblique insertion into the pelvic inlet, known as cephalopelvic uneven obliquity. If the anterior parietal bone enters first, and the sagittal suture is偏后，it is called anterior uneven obliquity; if the posterior parietal bone enters first, and the sagittal suture is偏前，it is called posterior uneven obliquity. When both parietal bones of the fetal head pass through the pelvic inlet plane, it can be delivered through the vagina smoothly.

　　4. Treatment of Three Planes of the Pelvis Being Narrow

　　It is mainly the brachycephalic pelvis. If the fetus is not large and the cephalopelvic fit is good, labor can be attempted. If the fetus is large and there is absolute cephalopelvic disproportion, and the fetus cannot pass through the birth canal, cesarean section should be performed as soon as possible.

　　5. Treatment of Malformed Pelvis

　　The analysis is specific to the type, degree of narrowness, fetal size, and labor force of the malformed pelvis. If the malformation is severe and the cephalopelvic disproportion is obvious, cesarean section should be performed in a timely manner.