Premature detachment normally situated placenta

Normally situated placenta, usually prematurely not separated because it is placed in the upper segment of the uterus, i.e. above the part of the uterus, which is subject to greater tensile strength and is called the lower segment. Progressive little stretching of the uterus is normally located placenta does not influence, in contrast to what was observed in case of presentation of the latter. With the reduction of the uterus placenta is subject only to the pressure to which it easily adapts thanks to its spongy structure. And most importantly, using neuro-hormonal regulation during pregnancy reduces the excitability of nervous-muscular apparatus of the uterus in General, and most significantly - at the location of the placenta. The decrease in excitability of the uterus is due to the diffusion of hormone yellow body, produced in the placenta. As a result, the muscles of the uterus is maintained in the condition necessary tone without any visible signs of contraction.
Detachment and the birth of the placenta normally occur only when these conditions change, which is connected with a birth of the child. The process of detachment of the placenta from the uterine wall begins either in the Central or peripheral part of the placenta and captures one or another course. Prerequisites for breaking the link between the placenta and the uterine wall created already at the end of pregnancy, when the major layers of the decidual membrane of the uterus occurs regressive and degenerative changes, which consist in the fact that the walls of the spongy layer become thin and loose. Meanwhile, they contain vessels relatively large size, which runs a large amount of blood. The vessels on the surface of partitions strongly twists and loose connective tissue support, that is predisposing condition their rupture.
Any, even the slightest violation of communication between the placenta and the uterine wall is accompanied by bleeding and education retroplatsentarno hematoma. Hematoma, first minor, pushes the surrounding tissue and causes further violation of vessels, resulting in bleeding increases.
In normal pregnancy, as a rule, premature detachment of the placenta does not happen. This is because the placenta has considerable flexibility and relatively easily adaptable to different spatial changes in the place of its location.
Premature detachment normally situated placenta occurs only if there is a particularly favorable for this process changes in a woman's body and associated violations of structural-morphological character of the uterus and the placenta. Due to the presence of the person gemorroidalnah type placentation every branch of the CVS inevitably leads to the opening of the blood vessels, and therefore an rootdelay, as well as appropriate retraction of the muscular layers of the uterus can't happen (in the cavity of the uterus is the fruit!), the bleeding is progressing, and it will be the more, than more villus (areas of the placenta) application.
As a rule, the reason for the detachment of the placenta are changes in the neural and neuro-hormonal mechanisms leading to change the reflex reaction of the uterus and disturbances of hemodynamics. Therefore, the functional state of the higher nervous activity of a pregnant woman, a doctor should give full attention.
Sudden changes coming in neuro-psychic state of women (fear, nervous shock), often associated with various external factors (bruises, shock, drop, foxes, etc.,), sometimes seemingly very little, and sometimes even without any connection with the latter, may be the proximate cause of this kind of complications.
The mechanism of occurrence of premature detachment is represented in the following form. When frightened or nervous breakdown occurs sharp simpatoliticescoe narrowing of peripheral vessels with simultaneous parasympathicotonia expansion in the area, innerved n. splanchnicus. Moving mass of blood from the skin and muscles of the abdominal cavity organs, including the uterus. As a result, increases static and dynamic loading on vessels that are easily torn and are therefore created foci of hemorrhage in decidual membrane, leading to detachment of the placenta.
However, the fact of blood redistribution in itself, without prior morphological changes in tissues of the uterus, its vessels and in the placenta of the above phenomena is.
The morphological changes that usually occur in women under each of physiological pregnancy, are of a completely different nature from those of them who have before this pregnancy were in the womb certain changes congenital (hypoplasia, infantilism) or acquired character (inflammatory, traumatic or novoobrazovannogo origin). This kind of changes typically affect in varying degrees, all layers of the uterus, but particularly are expressed in decidua serotina.
All these changes that are found in the tissues of the uterus (especially in the lining of her shell), and the placenta, are in close connection with the violation of metabolism, in particular enzyme.
The mucous membrane of the uterus is rich in hyaluronic acid, which is closely biological unity with the enzyme hyaluronidase. The violations in the biological system "hyaluronic acid - hyaluronidase", can disrupt the natural process sinestesia fertilized egg to the uterus wall, namely: when activity of hyaluronidase reduces adhesive, cementing the property of hyaluronic acid. Thanks to this, the placenta is attached to the wall of the uterus very loosely and connecting it with the past is not strong. Hence, in a number of favorable factors placenta relatively easily and quickly can be rejected from the uterine wall (I. E. Magrachev).
If there are changes in the endometrium, caused by previous illnesses, the connection between the placenta and the uterine wall also is not strong enough, while the size of the placenta, has been quite extensive, and its amendments deprive her of the possibility to adapt to the changing spatial relations.
In the pathogenesis of the disease has a significant role change in the functional state of cardiovascular system (increased fragility and increased permeability) of the whole organism and, in particular, vessels metoclopeamide system; the walls of blood vessels become fragile and poorly adapted to the redistribution of masses of blood that often occurs in women during pregnancy under the influence of mechanical, neurohormonal, and other factors, equally vessels are not able to resist and increased pressure, or small mechanical stress and easily broken.
All of the above changes lead to thrombosis and hemorrhage in majorsince space, which undoubtedly facilitates the possibility of premature detachment of the placenta (K. F. Slavic, Weis).
When the detachment of the placenta, as was said above, the main role is played by the change of the walls of the maternal blood vessels of the latter, which is particularly common when the glomerulonephritis and toxemia pregnancy. About the correctness of this assumption says frequent combination of placental abruption with renal impairment and albuminuria (42.1%) and eclampsia (8-8,3%), indicating a disease of the whole body. Albuminuria is a common symptom of the disease of the organism as a result of impaired metabolism, which in some cases may be in the form of eclampsia, others may lead to the formation retroplatsentarno hematoma, followed by the detachment of the placenta, and in the third - to the combination of eclampsia with premature detachment.

Changes of the vascular system for jade are the main cause of hemorrhage (in the fundus of the eye, the brain), uterine bleeding in non-pregnant and premature detachment of the placenta in pregnant women and mothers. The fragility of vascular walls and their inability to resist increased arterial blood pressure, usually observed for jade, contribute to the formation of hemorrhage, retinal detachment of the placenta and the emergence of white heart attacks.
Thus, conditions for the emergence of hemorrhage in decidua serotina are high blood pressure, change of vascular walls and malnutrition tissue due to thrombosis.
Among other causes of premature detachment of the placenta, it should be noted stroke, acting directly on the area of location of the placenta, and cut the umbilical cord.
The relationship between premature detachment of the placenta and the presence of short umbilical cord is expressed, according to some obstetricians, that at progress fetal umbilical, due to the "absolute" or "relative" shortening, stretched so much that causes the separation of the placenta. However E. I. Povolotskii notes that korotkoi umbilical cord as ethnological point of detachment plays a minor role (in its material - 0.6%).
To premature detachment of the placenta can lead belated opening Crowded bubble, for continuous positive promotion intact fetal bag has lead the action on the placenta separates from the wall of the uterus.
Premature detachment of the placenta and can sometimes cause rapid emptying of the uterus in cases of sudden discharge of a large number of amniotic fluid or expulsion of one of fetuses with twins. These factors also play a role in the emergence of placental abruption in graves ' disease and circulatory disorders. Sudden blood pressure and sharp fluctuations in blood pressure lead to rupture of the spongy walls and blood vessels and the formation of hemorrhage.
Placental detachment can occur when a narrow pelvis, when running the transverse position of the fetus, bicornuate uterus, owing to the abnormal spasmodic contractions of its muscular system, in which there restretching lower segment, thickening of the walls of the womb and decrease the size of the placental site.
Premature detachment of the placenta can occur in very different throughout, ranging from small plots to separate from the uterine wall entire surface of the placenta. With the detachment of a small area and minor bleeding on the surface of placenta (after her birth), there are small blood clots associated with primary cloth.
The emergence of minor internal bleeding before delivery is usually not recognized due to the lack of distinct symptoms, the diagnosis is established only after the birth when viewed placenta.
In the absence of clinical symptoms of retinal on maternal surface born placenta sometimes revealed organized blood clots.
When a significant change of vascular walls and a sharp increase in blood pressure blood shed abroad it forms a large hematoma, the placenta detaches from the uterus over a large area.
The appearance of external bleeding depends on the localization of hematomas.
If a hematoma is located in peripheral Department of the placenta, the external bleeding usually occurs (Fig. 62). If a hematoma is located in the centre of the placenta, the external bleeding, and is an accumulation of blood between the placenta and the uterine wall (Fig. 63); described the deaths of women in the absence of external bleeding.

Fig. 62. Premature detachment normally situated placenta. Detachment of the edge of the placenta. External bleeding.

Fig. 63. Premature detachment normally situated placenta. Detachment in the Central part. External bleeding not.

Formed hematoma so stretches the placental site that the last protrudes into the abdominal cavity. The pressure of accumulated blood on the wall of the uterus can be so strong that muscle, and serous cover of the uterus cracks; all the uterine wall is soaked with blood that sometimes gets in parametri (apoplexies uteroplacentaris Couvelair). In the abdominal cavity find any serous or sero-bloody fluid, and if the uterine wall is broken - that's shed abroad blood. The blood poured out between the edge of the placenta and the uterine wall, usually makes its way out. This fact has its positive and negative sides. External bleeding contributes, on the one hand, the reduction of intrauterine pressure and eliminates the hyperextension of the uterine wall, and on the other, the entry of new units of blood from the revelations of the vessels of the uterus.
In rare cases, blood pouring out not outside, and penetrates through the broken shell inside of the ovum and colors the amniotic fluid. If the lower segment not implemented large predlagay part, detached placenta reaches the internal OS, and can be born with fetal or even before it. The last complication is called prolapsus placentae.