What is Natural Childbirth?

Natural delivery is a form of delivery. The process of the fetus and its appendages from the beginning of labor to full delivery from the mother at the age of 28 weeks and above is called childbirth. Delivery during the 28th week of pregnancy to the 37th week of pregnancy is called preterm birth. Delivery between 37 weeks and 42 weeks of pregnancy is termed term delivery; delivery at 42 weeks and after pregnancy is termed overdue delivery.

Cuckoo	(Chief physician)	Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University
Qiu Hui	(Attending physician)	Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University
Li Jie	(Resident)	Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University

Definition of natural delivery

The process of the fetus and its appendages from the beginning of labor to full delivery from the mother at the age of 28 weeks and above is called childbirth. Delivery during the 28th week of pregnancy to the 37th week of pregnancy is called preterm birth. Delivery between 37 weeks and 42 weeks of pregnancy is termed term delivery; delivery at 42 weeks and after pregnancy is termed overdue delivery.

Motives of natural delivery

The reasons for the onset of childbirth are complex and unknown until now. Many theories have tried to explain them, but they are difficult to elaborate completely. They are generally recognized as the result of a combination of factors.

Mechanical theory of natural delivery

As pregnancy progresses, the uterus changes accordingly. The uterus is in a resting state in the early and middle stages of pregnancy and is not sensitive to mechanical and chemical stimuli. In addition, the anatomical structure of the cervix is stable to ensure that the uterus can tolerate the load of the fetus and its appendages. In the end of pregnancy, the pressure in the uterine cavity increases, the uterine muscle wall and decidua are compressed, and the mechanoreceptors of the muscle wall are stimulated. At the same time, the fetal exposed part compresses the lower uterine segment and the inner cervix of the uterus, and the mechanical expansion occurs. The uterine contraction is caused by the release of oxytocin from the pituitary gland.

Theory of Endocrine Control in Natural Delivery

Changes in prostaglandins, oxytocins, oxytocin receptors, estrogen, progesterone, and endothelin in late pregnancy pregnant women can affect uterine contraction and cause labor to start. But there is no clear experiment to indicate which hormone is the cause of the onset of labor.

Theory of natural delivery nerve

The uterus is mainly innervated by the autonomic nerve, and the sympathetic nerve excites the -adrenergic receptors in the myometrium and promotes uterine contraction. Acetylcholine strengthens uterine contraction by increasing the permeability of the uterine muscle cell membrane to Na.

In summary, multiple factors such as mechanical stimulation, endocrine changes, and release of nerve media at the end of pregnancy can promote the formation of the lower uterine segment and the gradual softening and maturation of the cervix. The lower uterine segment and the mature cervix are passively expanded by intrauterine pressure and secondary prostate The release of oxytocin and oxytocin, the formation of uterine muscle cell gaps and the increase of calcium ion concentration in uterine muscle cells, changes the uterus from a stable state during pregnancy to an excited state during childbirth, and the uterine muscles appear to contract regularly, resulting in the onset of labor ^{[1 ]} .

Factors Affecting Natural Delivery

The factors that determine childbirth are fertility, birth canal, fetus, and psycho-psychological factors. If all factors are normal and can adapt to each other, the fetus can be delivered naturally through the vagina, which is normal delivery. Normal delivery relies on fertility to force the fetus out, and a sufficiently large bone birth canal and soft birth canal should be expanded to allow the fetus to pass. The productivity is affected by fetal size, fetal position and birth canal. In addition, it is also affected by psychological factors.

Threatened labor

The presence of symptoms that presage labor will soon be called threatened labor.

1. False labor: Pregnant women often experience false labor before delivery starts. Its characteristics are: the duration of contractions is short, <30 seconds, and is not constant, the interval is long and irregular, and the intensity of contractions does not increase. Discomfort during the contraction is mainly concentrated in the lower abdomen, the cervical canal is not shortened, and the cervix is not dilated. It often appears at night and disappears in the early morning. Administration of strong sedative drugs can inhibit contractions.

2. Fetal sensation of decline: The pregnant woman feels the pressure on the upper abdomen disappears, eats more than before, and breathes lighter than before. The exposed part of the fetus enters the pelvic entrance, which lowers the position of the palace floor.

3. See red: within 24 to 48 hours before delivery, due to the separation of the fetal membrane near the inner cervix from the uterine wall there, there is a small amount of bleeding from the ruptured capillaries, which is mixed with the mucus plugs in the cervical canal and discharged. Red is a more reliable sign that childbirth is about to begin. If vaginal bleeding exceeds normal menstrual volume, bleeding in late pregnancy should be considered.

Natural labor

The sign of labor initiation is a regular and gradually increasing uterine contraction, lasting 30 seconds or more, with a gap of 5 to 6 minutes, accompanied by progressive disappearance of the cervical canal, dilation of the uterine opening and decline of the fetal exposed part. Use of strong sedatives cannot inhibit labor.

Total natural labor and labor stages

The total labor process is the whole process of childbirth, which refers to the regular contraction from the beginning until the fetal placenta is delivered. Divided into 3 labor processes

The first stage of labor: refers to the beginning of labor until the Miyaguchi is fully expanded. The uterine cervix is tighter and the cervix expands slowly, taking 11 to 12 hours. The uterine cervix is loose, and the cervix expands rapidly, taking 6 to 8 hours.

The second stage of labor: the process from full expansion of the uterine uterus to the delivery of the fetus. It takes 1 to 2 hours for a primiparous woman, and it should not exceed 2 hours; it can usually be completed in a few minutes by a woman, and it can take up to 1 hour, but it should not exceed 1 hour.

The third stage of labor: from the delivery of the fetus to the delivery of the placenta and placenta, that is, the process of placenta peeling and delivery, which takes 5 to 15 minutes and should not exceed 30 minutes.

Clinical process and treatment of natural labor

Natural delivery

Clinical manifestations: regular contractions, dilated uterine orifices, decreased fetal head, and ruptured membranes

Treatment: Pay attention to the patient's contractions, fetal heart rate, dilation of the uterine uterus and fetal head. The mental state of the mother affects the contractions and the progress of the labor process. The first childbirth has a long labor process and is prone to anxiety, tension and irritability. The mother should be comforted and the mother should work closely with the midwife to facilitate the delivery. In order to ensure energy and physical energy, pregnant women should be encouraged to eat a small number of times, eat high-calorie digestible food, and pay attention to intake of sufficient water. And encourage the mother to urinate once every 2 to 4 hours, so as not to affect the contraction of the bladder and the decline of the fetal head. Difficulty urination, catheterization if necessary.

Second childbirth

Clinical manifestations: contractions are stronger than before. When the fetal head is lowered to the pelvic floor to compress the pelvic floor tissue, the mother feels defecation and holds her breath involuntarily. When the contraction of the fetus is exposed at the vaginal opening, the exposed part continuously increases. During the intermittent period of contraction, the fetal head is retracted into the vagina, which is called fetal head dew exposure. When the double parietal diameter of the fetal head crosses the pelvic exit, the fetal head no longer retracts when the contractions are intermittent, which is called the fetal head crown. The labor process continued to progress, and the fetal head occipital bone was exposed under the pubic arch, with an upward motion, and the fetus's forehead, nose, mouth and palate were delivered in succession. After the fetal head was delivered, the fetal head was reset and rotated externally, and then the front and back shoulders were also delivered in succession, and the carcass was delivered smoothly.

Treatment: Closely monitor the fetal heart rate, instruct the mother to hold her breath, and deliver the baby.

Third stage of natural delivery

Clinical manifestations: After the fetus is delivered, the uterine floor is lowered to the navel level, the mother feels slightly relaxed, the uterine contractions reappear a few minutes later, and the placenta is stripped. The uterus continues to contract, and the stripped area continues to expand until the placenta is completely stripped and delivered.

Treatment: newborns clean the airways, handle the umbilical cord, and score the newborns. Assist placenta delivery, check placenta, fetal membranes, check soft birth canal, and prevent postpartum hemorrhage.