Normal succession period

Usually at every birth, woman loses some blood. In physiological delivery degree of blood loss is 50-300 ml and always associated with the third stage of labor.
Currently, in accordance with decision V Plenum of the Council of obstetric-gynecological care, held in 1954, is considered to be the blood loss in the third stage of labor within 250 ml of physiological, blood loss of more than 250 ml, 400 ml - edge, and over 400 ml - excessive (pathological).
A greater degree of blood loss in succession period usually indicates functional disorders of the uterus. This becomes clear if we remember anatomical and physiological basis of the process of detachment of the placenta from the uterine wall. If by the beginning of the delivery volume of the uterus reaches 5000-6000 cm3, and the inner surface of the uterus is 941 cm2, after the birth of a fetus and rear discharge of amniotic fluid volume of the uterus is greatly reduced and at the same time sharply reduced the inner surface of the uterus. This creates spatial mismatch (offset) of the squares of the uterus and the placenta, as fabric latter does not possess the property of reducing inherent in muscle tissue, and its area amounts to 324 cm2.
When you change these relations on the inner surface of the uterus at the location of the placenta arise like "fold", which gives impetus to the detachment of placental tissue.
At the same time sharply reduced and intrauterine pressure. This leads to the fact that the placenta is gradually separated from the uterine wall, and then the whole comes out of the body outside.
Detachment of the placenta is accompanied by changes in the profile (form height and position of the uterus. The fundus of the uterus, which was after the expulsion of the fetus at the level of the navel, after the detachment of the placenta rises above while narrowing the diameter of the uterus and education mild elevation above the symphysis (sign K. Schrader), the uterus changes spherical form on ovoid, the contours become more clear and texture is more dense.
The process of detachment of the placenta from the uterine wall begins, according to A. Krasovskogo, during the last expulsive efforts.
Veracruz (1918), and then Burton-brown (1949) by the method of contrast radiography found that the separation of the placenta begins during the first fight after birth the fetus.
On average, from the moment of birth the fetus before birth, the placenta takes 15 minutes Unconditional value in the detachment of the placenta from the uterine wall and then allocate it to the surface, and therefore, the extent of blood loss is blood clotting in the placenta (majorsince spaces, chorion and basal membrane with deposition in them fibrin).
After coagulation come fibrinolysis processes that lead to the loosening of the decidua spongjosa or to melting of fibrin in decidual shell. This enzyme phase, according to Puder, is the first phase of the functional process of placental abruption.
Thus, the detachment of the placenta from the uterine wall, and then its allocation of outside help:
1. Changed the spatial relationship between the squares of the placenta and the inner surface of the uterus.
2. The blood clotting process occurring in the placenta which ceases to allocate to the uterus hormone yellow body and thus have electoral relaxing effect on the placental site of the uterus.
3. Own weight separating the placenta, which pulls it down (out); in the "hanging down of the" placenta inevitably will increase the irritation of the receptor apparatus of the uterus, resulting retroplatsentarno hematoma in most cases is a consequence of the outbreak of placental abruption, and not its cause.
The number of supporting factors contributing to the process of detachment and the birth of the placenta, is a number of factors, which will be discussed further.
So, W. J. the Mikeladze noted that the duration of succession period is considerably reduced if the mother in the third stage of labor is in position on the side appropriate to the existing position of the fetus. According to him, under this condition, the duration of the third period is 7-9 minutes
When women are on the opposite side, not the appropriate position of the fetus, slightly increases the duration of the third period (up to 9-10 min).
In accordance with the mechanism of placental abruption, as mentioned above, is the duration of a succession period and to some extent blood loss, which in physiological delivery varies between 250 ml of blood from venous sinuses decidua serotina. The separation of the placenta takes place in the spongy layer of the falling shell that contains a large number of developed glands with very thin reborn walls. In some cases the separation of the placenta starts from the bottom and gradually extends towards the centre, in others, on the contrary, the detachment of the placenta begins with Central and peripheral parts are separated last (80%) (Fig. 104).

Fig. 104. Various ways and stages of separation and the expulsion of the placenta. and Central branch; - a regional division.

The last type of detachment better, since it rarely happens delay in the uterine cavity shells and parts of the placenta. The parts of shells, linger in the uterus, usually depart on the 3-4th day. Shell left in the uterus completely, usually leave independently on 8-10 day. To strive for manual separation membranes, especially at partial delays should not be.
In positive cases, if there is bleeding is due to complete delay shells, highlight them by hand.
Besides these, there is another kind of biomechanism detachment and allocation of the placenta; it is that the placental abruption occurs simultaneously on all surface. The separation of the placenta in this type of biomechanism observed in single cases. Stop bleeding in a normal uterus after birth, the placenta is mainly due to compression of the lumen of the blood vessels twitch muscle fibers and thrombosis, as well as due to tightening thin walls where are the vessels. Good reduction of muscles of the uterus occurs only in the complete liberation of the cavity from the placenta.
The process of detachment of the placenta largely depends on the termination of placental circulation and regressive changes in the Placenta.
Histological studies have established that in the last months of pregnancy in the placenta comes fat and hyaline rebirth stroma and cells decidua basalis favours a detachment.
Detachment of the placenta from her bed and release it outside help reduce abdominal muscles and wall muscles of the vaginal walls, in particular the posterior vaginal wall.
During uterine contractions of the muscles of the vagina are shortened, as if straight, and the back wall of the vagina becomes less concave. This fact contributes to the expulsion of the placenta out. Similarly in the detachment of the placenta plays the role and gravity of the placenta.