Biomechanism of labor in the anterior and posterior view of the occipital presentation

Biomechanism of labor in the anterior and posterior view of the occipital presentation

About delivery in the forward view of the occipital presentation

The biological mechanism of childbirth represents a set of movements that the fetus performs by passing through the mother's birth canal. They are flexible, extensor and rotational.

Occipital presentation is the posture of the fetus in the uterus, in which its head is in a bent state, and the occiput is located most low. Obstetrical practice states that births from this arrangement of the fetus are about 96% of what is happening.

The first moment of the birth process is the bending of the head. In this case, the cervical spine of the fetus bends, its chin approaches the breast, and the nape falls down. The child's forehead lingers over the entrance to the small pelvis. At a forward view of an occipital presentation the head is bent to a small oblique size. Further, in a state of moderate flexion (synclatically) it is inserted into the entrance to the small pelvis.

The second moment of birth is the internal (correct) turn of the fetal head. It continues to move forward into the pelvis and overcomes the opposition caused by the shape of the birth canal. The baby's head rotates around its longitudinal axis. At the same time, the nape approaches the lap joint and slides along the side wall of the mother's pelvis.

The third moment of birth is the breakout At the same time, the nape approaches the lap joint and slides along the side wall of the mother's pelvis.

The third moment of birth is the breakout At the same time, the nape approaches the lap joint and slides along the side wall of the mother's pelvis.

The third moment of birth is the breakoutBanning the baby's head. She then moves along the birth canal. At physiological birth, extension of the organ occurs in the exit from the pelvis. The suboccipitary fossa rests against the base of the lateral articulation. So there is a fulcrum. The head is fully bent for several attempts. Through the vulvar ring there are the back of the head, the forehead, the face, the chin.

The fourth moment of delivery is the inner turn of the shoulder of the fetus and the outer turn of his head.

After the exit from the mother's womb, the rest of the body appears, due to the fact that the birth canal is prepared by the appearance of the head.

About the mechanism of birth in the back view of the occipital presentation

In practice, only 1% of such presentations the child appears in the back view. It means, that his head emerges from the mother's ancestral ways with the back of his head facing the sacrum. The causes of atypical delivery are changes in the capacity of the small pelvis, inferiority of the uterine muscles, dead or premature fetus.

The first moment of the birth process - the bending of the head - occurs in such a way that its sagittal seam is established syncally. The organ passes through a wide cavity of the small pelvis so that the leading point is the point on this seam near the large fontanel. The second moment of delivery is the wrong (inner) turn of the baby's head. The swept seam is rotated by 45 А. or 90 А C. . Thus, a small fontanelle is located behind the sacrum, a large font - in front of the heart. The third point is the maximum flexion of the head under the lower edge of the pubic articulation. As a result, the occiput is born, and then the fourth moment of the generic process takes place - its extension under the action of the generic forces. Further from underneath the forehead appears first, then his face, which is turned to the bosom. Then the biological process of birth occurs in exactly the same way as in the forward view of the occipital presentation. The fifth moment is an external turn of the head and an inner turn of the shoulders.

So, in the biological mechanism of the birth of a baby with this type of occipital presentation, the most difficult moment is included - the maximum bending of the baby's head. That's why the period of his expulsion is prolonged and requires additional burden on the parturient woman, the work of the abdominal press and the muscles of the uterus. In this regard, the soft tissues of the pelvis and the perineum are subjected to a powerful stretching. In most cases, they are injured. The protracted process of delivery, as well as additional pressure from the birth canal often lead to fetal asphyxia. This is due to a violation of the baby's cerebral circulation.

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