Premature placental abruption is an early separation of the placenta from the walls of the uterus that occurred before the birth of the fetus. The classic manifestations are pain, bleeding, tension of the uterine muscles, fetal disorders. Premature placental abruption is diagnosed based on the complaints of a pregnant woman, vaginal examination data, ultrasound. Treatment consists in carrying out tocolytic, antispasmodic, hemostatic, antianemic therapy; in some cases, the question of operative delivery is raised.
Premature placental abruption is a serious complication that endangers the life of the mother and fetus and requires urgent medical measures. In obstetrics and gynecology, premature detachment of the normally located placenta is distinguished when it is localized in the upper parts of the uterus, on the walls of the body or bottom, and detachment of the placenta previa located in the uterine pharynx. Premature placental abruption can develop both during pregnancy and during childbirth. The frequency of this pathology occurs in 0.4-1.4% of all pregnancies.
During pregnancy, the placenta is pressured, on the one hand, by the muscles of the uterus, on the other – by the fetal egg and amniotic fluid. Normally, these forces are balanced by a significant elasticity of the placental tissue due to its spongy structure and a lesser ability to contract the area of the uterus to which the placenta is attached. These mechanisms in normal pregnancy exclude the development of premature placental abruption.
Modern views on the etiology of premature placental abruption as a leading factor distinguish the development of vasculopathy – vascular changes that disrupt uteroplacental circulation. Vascular disorders can occur if a pregnant woman has somatic diseases (pyelonephritis, hypertension, obesity, diabetes mellitus), toxicosis (gestosis), etc.
Vasculopathy is characterized by increased permeability, fragility and fragility of capillaries, multiple heart attacks and thrombosis in the placental tissue. Violation of the contact of the placenta and the uterine wall is accompanied by the accumulation of blood between the uterine wall and the placenta with the formation of a retroplacental (post-placental) hematoma, further aggravating placental abruption.
There is a theory that the development of premature placental abruption is a consequence of chronically occurring uteroplacental insufficiency, the causes of which lie in inflammatory, degenerative and other pathological processes of the uterus and placenta. Such changes occur in chronic endometritis, endocervicitis, uterine fibroids, anatomical abnormalities of the uterus, post-term pregnancy.
Abdominal injuries, multiple pregnancies, polyhydramnios, a short umbilical cord, multiple births or abortions, delayed opening of the fetal bladder, anemia, bad habits, autoimmune diseases are also identified as risk factors for premature placental abruption. In rare cases, premature placental abruption develops in response to the introduction of any drugs (protein solutions, donor blood).
Options for premature placental abruption
According to the area of the rejected site, partial and complete total premature detachment of the placenta is distinguished. Total (complete) detachment is accompanied by the death of the child due to the cessation of gas exchange between the organisms of the mother and fetus.
Partial placental abruption occurs in a limited area and may have a progressive or non-progressive course. With the non-progressive nature of premature placental abruption, thrombosis of the uterine vessels occurs and further separation of the placenta is suspended. The subsequent course of pregnancy and childbirth is not violated. In the case of progressive detachment, the hematoma increases, the separation of the placenta continues, which leads to a pathological course of pregnancy and childbirth.
According to the localization of the placental tissue separation zone, marginal (peripheral) and central premature placental abruption are isolated. In the case of premature detachment of the central part of the placenta, external bleeding may be absent; exfoliation of the marginal part is usually accompanied by blood flowing out of the genital tract. In the absence of external bleeding, blood permeates the thickness of the myometrium, which leads to damage to the neuromuscular apparatus of the uterus, loss of its excitability and contractility. In severe cases, blood can enter the amniotic fluid and the abdominal cavity.
Signs of premature placental abruption include bleeding, pain and tension in the uterus, hypoxia and cardiac disorders on the part of the fetus. Bleeding with premature placental abruption can be external, internal and mixed (internal-external) with the release of scarlet or dark blood, depending on the prescription of detachment. It is difficult to determine the amount of blood loss in internal or internal-external bleeding, therefore, in practice, they focus on the volume of external blood loss and the condition of the pregnant woman (pulse, pressure, Hb, etc.).
Uterine tension and abdominal pain with premature placental abruption are almost always present. The pain can be dull, paroxysmal, with irradiation into the womb, hip or lower back, local or diffuse. On palpation, the gynecologist determines that the uterus is tense and has a dense consistency. The degree of intrauterine fetal suffering with premature placental abruption is due to the area of the calved placental tissue. With detachment of more than 1/4 of the placenta area, the fetus begins to experience hypoxia, with detachment of 1/3 – severe hypoxia; with rejection of more than 1/3-1/2 of the placenta surface, stillbirth.
According to the severity of clinical manifestations, there are mild, moderate and severe forms of premature placental abruption. A mild degree of premature placental abruption may not manifest itself with distinct symptoms and is often detected during routine ultrasound or during examination of the placenta after childbirth. The moderate form of pathology is characterized by abdominal pain and minor discharge of blood and clots from the genital tract. Palpation determines a somewhat tense uterus, local moderate soreness. During fetal auscultation, cardiac disorders are heard, indicating hypoxia of varying degrees.
With a severe form of premature placental abruption, there are sudden intense bursting abdominal pains, sharp weakness, dizziness, sometimes fainting, pallor of the skin, tachycardia, hypotension. A moderate amount of dark blood is released from the genital tract. There is a sharp tension and asymmetry of the uterus: painful protrusion is palpated on one side of it. Fetal heartbeat is not determined auscultatively.
With the expanded manifestations of premature placental abruption, diagnosis is not difficult. This takes into account the presence of pain syndrome, bleeding, hemodynamic disorders, hypoxic suffering of the fetus. Gynecological examination reveals hypertonicity of the uterus, its local or diffuse soreness, asymmetry.
In the process of ultrasound, the localization of the placenta, the size of the detachment site is established. Dopplerography of uteroplacental blood flow reveals violations of transplacental hemodynamics. The degree of fetal hypoxia is determined by fetal cardiotocography or phonocardiography. A slight degree of premature detachment can be detected when examining an already born placenta by a characteristic small indentation on its surface filled with dark blood clots.
Tactics for premature placental abruption depends on the time of pathology development (pregnancy, childbirth), the severity of bleeding, the condition of the pregnant woman and the fetus. Pregnant women with signs of premature placental abruption are hospitalized in the obstetric department of the hospital.
With partial non-progressive detachment for up to 36 weeks, bed rest, antispasmodic, tocolytic, hemostatic, antianemic therapy is prescribed. Treatment is carried out under the control of coagulogram, dynamic ultrasound and Dopplerography. With indications of the progression of premature placental abruption, there is a need for early delivery. When the birth canal is ready (shortening, softening of the cervix, patency of the cervical canal), an amniotomy is performed; childbirth can be carried out naturally with careful cardiac monitoring.
With moderate to severe premature placental abruption, the choice is made in favor of operative delivery. With a severe degree of detachment, caesarean section is performed regardless of the gestation period and the viability of the fetus. After fetal extraction and placenta separation, clots are removed, the walls of the uterus are examined, the condition of the myometrium is clarified. With pronounced changes in the uterus, hysterectomy is indicated.
Regardless of the method of delivery, restoration of blood loss, antishock therapy, correction of anemia and blood clotting disorders using infusion and transfusion therapy are carried out. To prevent postpartum bleeding, uterotonic drugs (oxytocin, prostaglandins, methylergometrine) are prescribed.
Prognosis and prevention
The mild form of non-progressive premature placental abruption is prognostically the most favorable. With a more severe course, there is a danger for the pregnant woman and the fetus. In severe cases, intrauterine fetal death may occur. The main threat to a woman is the development of hemorrhagic shock with DIC syndrome.
Prevention consists in timely therapy of general somatic and gynecological pathology of women planning pregnancy; treatment of late toxicosis, dynamic monitoring of uteroplacental blood flow at all stages of pregnancy.