Photos of women giving birth to children

Delivery refers to the process that the fetus grows and matures and is discharged from the mother's uterus. The 40th week of pregnancy is full-term pregnancy. The fetus is mature and its weight fluctuates between 2,500 and 4,000 grams. At least 25% of newborns weighing less than 2,500 grams at birth have the characteristics of being pregnant for more than 37 weeks: rosy skin, full subcutaneous fat, less fetal fat and hair, obviously normal hair and nails, loud crying, boys' testicles falling into scrotum, and girls' labia majora covering clitoris and labia minora. Therefore, more than 20 years ago, some people advocated re-examining the concept of judging immaturity only by weight. The above situation does not belong to premature infants, but is full-term or expired, so it is called small-sized infants. This requires special attention after birth. During pregnancy, although the uterus is expanding day by day, the contraction of uterine smooth muscle has been very weak and basically in a calm state, so it will not cause the feeling of pregnant women. It was not until the day before delivery that the uterine contraction gradually strengthened. The contractions at this time have two physiological meanings. One is to squeeze the fetus, so that the menstrual period gradually turns to the normal position before labor in the uterus; The second is to promote the uterus to open to facilitate delivery. The following is a brief introduction from the aspects of delivery mechanism, delivery process and new delivery measures.

Mechanism of childbirth

How can the uterus contract strongly at the end of pregnancy? There is no clear answer to this question until today. The study of animals has accumulated evidence of the initial mechanism of childbirth, and it is considered that the existence of fetus is the key factor to cause childbirth; However, whether this idea can be applied to humans remains to be further studied. On the maternal side, more progesterone is secreted in the first two thirds of pregnancy, which can inhibit uterine contraction; In the later period of 1/3, the secretion of estrogen is more, which can increase the spontaneous contraction of uterine muscles and enhance the sensitivity to oxytocin, so the uterine contraction is more frequent, especially a few days before delivery. When the reproductive tract of pregnant women is stimulated after delivery, oxytocin can be secreted through nerve reflex, and oxytocin can strengthen uterine muscle contraction at this time.

It is also necessary to point out the influence of people's psychological activities on the delivery process. The delivery process is a very intense whole body activity process. In order to get through this process smoothly, pregnant women need to actively participate in this process. On the contrary, if you want to escape this process with fear and shyness, the effect will be counterproductive. This shows that brain activity can affect uterine contraction through the lower center.

(2) the delivery process and new delivery methods and measures

The process of human childbirth is usually divided into three stages. In the first stage, the uterine contraction frequency is low and the contractility is weak. Its main function is to enlarge the cervix. At the end of this stage, the capsule outside the fetus is broken and amniotic fluid is discharged. When the cervix has been completely opened and the fetal head has fallen into the pelvic cavity, the second stage begins. Since then, uterine contraction has become fast and powerful, called uterine contraction. The function of contraction is to squeeze the fetus out. Whenever there is sudden contraction, the parturient should cooperate with breath-holding exercise and close the glottis, so that the abdominal wall muscles and diaphragm are forced to contract, which is helpful for delivery. Usually, after this contraction occurs intermittently for two or three times, the uterus continues to contract strongly for 20-30 minutes. This is the third stage. The contraction at this stage is to squeeze the placenta out of the body and compress the venous sinus and damaged blood vessels in the uterine wall to avoid excessive bleeding. After the delivery process is completed, the uterus gradually shrinks, but it can never return to the state before pregnancy.

In addition to uterine contractility, abdominal pressure and levator ani contraction caused by contraction of abdominal muscles and diaphragm also help to promote fetal delivery. The birth canal is divided into bone birth canal and soft birth canal. The birth canal of bone is pelvis. When the fetus is delivered, a series of adaptive actions must be taken according to the shape and size of the pelvis. The soft birth canal is a curved tube composed of the soft tissues of the lower uterus, cervix, vagina and pelvic floor. Whether the fetus can be delivered smoothly depends on the fetal position, fetal size, fetal head plasticity and deformity. When the fetus passes through the birth canal, a series of rotations occur to adapt to the shape and size of the birth canal, so that the fetal head can fit the widest diameter line of each plane of the pelvis with the minimum diameter line to pass through the birth canal. This process is also called delivery mechanism, which includes six processes in turn: joint, descent, flexion, internal rotation, supination and external rotation. Among them, the connection, also known as entering the basin, means that the fetal biparietal diameter enters the pelvic entrance plane; Internal rotation makes the occipital part rotate 45 degrees forward, that is, the small chimney door turns under the pubic arch, so that the sagittal suture is consistent with the pelvic anteroposterior diameter, which is suitable for the characteristics that the anteroposterior diameter of the pelvic outlet is larger than the transverse diameter. The process is in the second stage of delivery; Not completed; External rotation means that the pillow rotates to the left with the rotation of the shoulder.

In the first stage of delivery, pay attention to uterine contraction, listen to fetal heart sounds, and pay attention to the time of capsules; Put a rubber finger cuff on your right index finger, apply a little lubricant, and do an anal examination gently to know the degree of cervical dilatation. Primiparas should be sent to the delivery room to prepare for delivery when the cervix is completely opened (about 10cm).