Revealing the secrets of the birth process from uterine contractions to delivery of the fetus

During pregnancy, although the uterus expands day by day, the contraction of uterine smooth muscle is always weak and basically in a calm state, so it will not cause discomfort to pregnant women. In the days leading up to delivery, uterine contractions gradually intensify.

birth mechanism

Animal studies have accumulated evidence for the initial mechanisms of labor, suggesting that the presence of the fetus is a critical factor in triggering labor; however, whether this hypothesis holds true for humans remains to be studied. For mothers, in the first 2/3 of pregnancy, progesterone is secreted more, which can inhibit uterine contraction; in the last 1/3, estrogen is secreted more, which can increase the spontaneous contraction of uterine muscle and uterine muscle contraction. Sensitive to oxytocin, so uterine contractions occur more frequently, especially in the days before labor. Stimulation of the maternal reproductive tract has begun after delivery, inducing the secretion of oxytocin through the reflex pathway, thereby strengthening the contraction of the uterine muscles.

It is also necessary to point out the impact of human psychological activities on the delivery process. The birth process is a very strenuous whole body activity. In order to complete this process smoothly, the mother needs to actively participate in the process; on the contrary, if she wants to avoid the process with fear and shyness, the effect will be counterproductive. This suggests that brain activity can influence uterine contractions through lower centers.

2. The delivery process and new delivery measures

The human birth process is usually divided into three stages. In the first stage, the frequency of uterine contractions is low and the contraction force is weak. Its main function is to further expand the cervix. Towards the end of this stage, the fetus\’s external sac ruptures and the amniotic fluid is expelled. The second stage begins when the cervix is ​​fully dilated and the baby\’s head has settled into the pelvic cavity. After that, the uterine contractions become faster and stronger, which are called labor contractions. The function of uterine contractions is to push the fetus out. Whenever uterine contractions occur, the mother should cooperate with breath-holding exercises, close the glottis, and contract the abdominal wall muscles and diaphragm to facilitate delivery. Usually, after two or three intermittent contractions, the uterus will continue to contract strongly for 20-30 minutes, which is the third stage. The contractions at this stage push the placenta out of the body, compress the venous sinuses and damaged blood vessels of the uterine wall, and prevent excessive bleeding. After the delivery process, the uterus gradually shrinks, but it cannot return to its pre-pregnancy state.

Factors that determine childbirth include, in addition to uterine contractility, which is the main force of the labor force, the contraction of the abdominal muscles and diaphragm and the abdominal pressure generated by the contraction of the levator ani muscle help promote the delivery of the fetus. The birth canal is divided into bony birth canal and soft birth canal. The bony birth canal is the pelvis. When the fetus is delivered, a series of adaptive actions must be taken based on the shape and size of the pelvic cavity. The soft birth canal is a curved tubular structure composed of the lower uterine segment, cervix, vagina, and pelvic floor soft tissue. Whether the fetus can be delivered successfully depends on the position of the fetus, the size of the fetus, the plasticity of the fetal head, and whether there are any malformations. When the fetus passes through the birth canal, a series of rotations will occur to adapt to the shape and size of the birth canal, so that the fetal head can adapt to the smallest diameter to the widest diameter of each plane of the pelvis and pass through the birth canal. This process is also called birthing machine rotation. Pack in turnIt includes six processes: jointing, descent, flexion, internal rotation, supine extension, and external rotation. Among them, the joint is also called the entry into the pelvis, which means that the biparietal diameter of the fetus enters the pelvic entrance plane; internal rotation rotates the occipital bone forward 45%, that is, the small funnel is rotated under the pubic arch to make the sagittal suture consistent with the anterior and posterior diameter of the pelvis to adapt The characteristic outlet of the anteroposterior diameter of the pelvis is greater than the transverse diameter. This process is completed in the second stage of delivery; external rotation means that the fetal headocciput rotates to the left as the fetal shoulder rotates.

In the first stage of delivery, pay attention to the uterine contractions, listen to the fetal heartbeat frequently, and pay attention to the timing of the fetal membranes; put the index finger of your right hand on the rubber finger cot, apply a little lubricant, and gently perform an anal examination to feel the degree of cervical dilation. wait. First-time mothers with a fully dilated uterus (about 10 cm) should be sent to the delivery room to wait for delivery.

Labor may occur at any time, day or night. Signs of labor usually appear when you seem to feel something but don\’t. First, you will experience increased urination frequency and discomfort when walking, and then you will feel a stiffness in your lower abdomen or some pain in your waist, similar to menstrual pain. This feeling tells you that the first contraction has started. The first contraction lasts 10-30 seconds, and the intervals are longer. Gradually prolonged uterine contractions, accompanied by brown, pink or bright red blood flowing out of the vagina, are called \”redness\”. Redness is the first sign that labor is about to begin. Redness usually occurs 24 to 48 hours before delivery.

A. The fundus of the uterus descends

A few weeks before delivery, because the fetal head is in the pelvis, the upper abdomen will feel lighter, breathing and appetite will also improve significantly, but the frequency of urination will increase and walking will become uncomfortable. This is why the fundus of the uterus descends.

B. Uterine contractions

A few days before labor, you will feel your abdomen is hard and accompanied by a slight bulge, indicating that the uterus is contracting. At this time, uterine contractions often last for a short time, and the intervals vary. It often appears at night and disappears in the morning, and the cervix will not dilate. So, you don\’t need to be nervous.

C. see red

2,448 hours before delivery, the vagina will discharge a small amount of bloody mucus, called redness. The redness may last for several days, with light discharge every day; it may also turn red suddenly. If you see a lot of redness that exceeds your usual menstrual flow, you should go to the hospital and contact your doctor or midwife promptly.

How to prepare for shipment? Disinfect the vulva; lay out sterile towels to prevent infection. In addition to general preparation, if you are at home, you should also have cutting and suturing supplies and medical cloths on hand. Midwives should disinfect their hands and put on sleeves and gloves. One umbilical scissor and two blood vessel clamps can be boiled for 10 minutes for disinfection; if it is an emergency delivery, burning alcohol can be used for disinfection. There are also plastic sheets, toilet paper, umbilical cord rolls, etc.

The last step is newborn care, ensuring that the trachea is not blocked and keeping warm. Neonates were scored immediately after delivery for signs of asphyxia. From the delivery of the fetus to the delivery of the placenta,It takes about 5-15 minutes, usually no more than half an hour. Postpartum patients should be observed in the delivery room for 2 hours, paying attention to uterine contractions, fundal height, vaginal bleeding, blood pressure, pulse, etc.

It\’s peak labor time and the baby is about to be born. It\’s exciting when the baby\’s head comes out because it\’s first touched and then quickly followed by hugs. There may be a noticeable sense of relief after giving birth. However, you may also feel wonder, tears of joy, or overwhelming feelings in the presence of your new baby.

1. The fetal head is close to the vaginal opening. Because the fetal head presses the pelvic floor, the vulva and anus will bulge. Soon you will see the fetal head, which moves forward with each contraction.

When it disappears, it may slide back a little. Don\’t be discouraged if this happens, it\’s completely normal.

2. When the top of the fetal head is visible, the midwife will tell you not to push too hard, because if the fetal head is delivered too quickly, the skin in your perineum may tear, so relax and use a few strokes. Seconds to catch your breath. If there is a risk of severe tearing, or the fetus is in danger, you will have an episiotomy. When the fetal head expands the vaginal opening, you will feel a tingling sensation, followed by numbness. This is because when the vaginal tissue expands very thin, it blocks nerve conduction.

3. When the head is delivered, the baby’s face faces down. The midwife may want to check the umbilical cord to make sure it is not wrapped around the baby\’s neck (the cord often wraps around the baby\’s head when the body is delivered). Then, the baby\’s head is turned to one side so that the head is in line with the shoulders. The midwife cleans the baby\’s eyes, nose, and mouth and, if necessary, sucks out fluid from the baby\’s respiratory tract.

4. During the next two contractions, the baby\’s body will slide out of the mother\’s body. Usually the midwife will put her hands under the baby\’s armpits to lift her out and place her on your abdomen, while the baby is still attached to the umbilical cord. At first the baby looks a little blue, his skin is covered in vernix and has streaks of blood, and he cries. If the baby\’s breathing is normal, he can be held immediately and held in his arms. In addition, the midwife will clean the baby\’s airway again and give oxygen if necessary.

5. After the fetus is delivered, there will still be uterine contractions to promote the delivery of the placenta, but the contractions at this time are relatively painless. Afterwards, the doctor will clean up the area. If there is a tear in the vulva, he will perform local suturing.

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