Retrochorial hematoma is a pathological condition of early gestation characterized by accumulation of blood between the outer shell of the blastocyst and the endometrium, detachment of the chorionic plate from the decidual shell. It is manifested by bloody discharge from the vagina, cramping pain in the lower abdomen, sometimes it is asymptomatic and is detected accidentally during a planned instrumental examination. It is diagnosed based on the analysis of complaints of a pregnant woman, the results of a clinical examination and ultrasonography. Conservative treatment – rest, medications.
O20.8 Other bleeding in early pregnancy
Retrochorial hematoma is an accumulation of blood in the retrochorial space, accompanied by partial rejection of the fetal egg. If earlier a hematoma was considered a predictor of impending placental insufficiency, in modern obstetrics there is a growing tendency to attribute it to the primary manifestation of this pathology. Hemorrhage occurs in the first trimester of pregnancy at the fifth to eleventh week. The frequency of occurrence is 1.3-3%, 18% of cases of bleeding in the early stages of gestation are associated with hematoma. Subchorial hematomas, even with adequate treatment, often lead to spontaneous abortion, and with the progression of pregnancy significantly increase the likelihood of obstetric and perinatal complications.
The causes of retrochorial hematomas have not been studied precisely to date. Hemorrhage between the membranes is a consequence of surface invasion of the trophoblast. This condition is most often caused by inadequate readiness for implantation of the endometrium and blastocyst due to changes in the quantity and quality of hormones produced by the ovaries, damage to the endometrial receptor apparatus and impaired immune regulation.
It is believed that the leading etiological factor is the insufficiency of the luteal phase and the immune conflict of the mother and embryo associated with reduced progesterone production. This explains the highest incidence of pathology in pregnancies that developed after ovarian stimulation (with in vitro fertilization, in women with hyperandrogenism), accompanied by insufficiency of the corpus luteum. Other reasons for the formation of retrochorial hematomas include:
- Infections. The occurrence of intrauterine hematoma at an early stage is often associated with chronic autoimmune endometritis, the triggering factor of which is infection. The probability of retrochorial hemorrhages increases with bacterial vaginosis, which is a source of nonspecific infection, and viral lesion. Contamination by a virus (herpes, Coxsackie, other enteroviruses, cytomegalovirus) of cytotrophoblast cells makes them a target of the body’s immune attack.
- Obstetric anamnesis. In women who have previously undergone cesarean section surgery, other surgical interventions on the uterus or repeated endometrial scraping, the risk is increased due to the possible ingress of an infectious agent into the uterine cavity and structural damage, as a result of which the process of endometrial formation is disrupted, the number of progestin receptors decreases, which negatively affects the modulation of the cellular immune response. Patients with habitual miscarriage are also at risk.
- Other uterine factors. Abnormal uterine development can lead to incomplete pre-gravidar transformation of the epithelium. The probability of pathology increases with fibroids (mainly submucous nodes).
- Hemodynamic and hemorheological disorders. Risk factors are arterial hypertension in the mother, congenital blood clotting disorders manifested by thrombophilia, chronic DIC syndrome. These pathological changes potentiate a decrease in the production of hormones and the synthesis of other proteins by the emerging placenta.
- Specific immune conditions. There is a predominance of cellular (Th-1 type) immune response, markers of which may be psoriasis, contact dermatitis, organ-specific immune lesions and habitual miscarriage. One of the reasons for the development of a hematoma with chorionic detachment is the close histological compatibility of the spouses.
The likelihood of pathology is affected by somatic diseases (diabetes mellitus, thyroid and liver diseases), household and industrial factors (atmospheric pollution, exposure to low or high temperatures, strong noise, reduced or unbalanced nutrition, hypovitaminosis), the age of the mother (less than eighteen, more than thirty years), chorion biopsy, trauma. More often, vascular damage is provoked by blunt abdominal trauma, prolonged exposure to vibration.
The pathogenesis of retrochorial hematoma is still unknown. If it was previously thought that a hematoma was a consequence of egg detachment and vascular amputation, now the concept of causation has radically changed. It is assumed that the pathology is associated with the inferiority of the gestational rearrangement of the spiral arteries of the uterus, as a result of which an early constant blood flow is established in the interstitial space.
During the first wave (at the fifth-seventh week of gestation) of invasion, the cytotrophoblast is introduced into the spiral arteries of the endometrium, the process is accompanied by the secretion of enzymes that destroy the connective tissue and muscle structures of the vessel walls with their subsequent replacement by fibrinoid mass. As a result, the diameter of the arteries increases significantly, the ability to contract is lost, and blood pressure decreases fourfold in their mouths. These changes are necessary for normal placentogenesis, maintenance of full-fledged life support of the fetus. The cytotrophoblast forms the inner lining of the arteries, completely blocking the lumen of 20-50% of the vessels and preventing the contact of the interstitial space with maternal blood at the first stage of placenta formation.
With incomplete restructuring of the arteries, the muscle-elastin fibers of the walls are replaced only partially by fibrin, the pressure in them is increased, cytotrophoblastic “plugs” blocking the vessels are defective, as a result of which the uteroplacental blood flow begins prematurely. Due to weak vascularization, chorionic villi during this period are not ready to receive arterial blood rich in oxygen and free radicals, which is due to their damage and the formation of a hematoma that exfoliates the chorial plate.
With the admission of a small volume of blood, a weak lesion of the retrochorial hematoma tissue is resolved over time, the development of the placenta and embryo continues. The increase in bleeding from the spiral arteries leads to an increase in formation, further detachment of the chorion, significant damage to the syncytiotrophoblast due to oxidative stress, embryo death, spontaneous abortion.
Taking into account the sizes determined during ultrasound examination, hematomas are classified as small (occupying up to 20% of the uterine area of the fetal egg), medium (20-50%), large (over 50%). According to the location, corporeal (located in the area of the walls, the bottom of the uterus) and supracervical (above the inner pharynx of the uterus) formations are distinguished. Small, as well as supracervical hematomas have a more favorable outcome – a small volume does not entail large-scale detachment, and the location near the cervical canal contributes to rapid emptying and regression. Early hemorrhages are formed at 5-7 weeks of gestation, late ones – at the eighth-eleventh. Hematomas are also distinguished by stages of development:
- Unorganized. “Fresh” hematomas that have arisen immediately after hemorrhage are a cavity filled with liquid blood. 12 hours after bleeding, the process of organization begins, accompanied by the formation and settling of clots. In case of continued bleeding, the absence of outflow of the contents of the hematoma increases in size, separating the fetal egg from the uterus.
- Organized. The organization of the hematoma indicates the cessation of bleeding. An organized hematoma consists of connective tissue and gradually decreases. Complete disappearance in 70% of pregnant women is observed after 1-2 months, in 30% of hematomas may persist until delivery.
Symptoms of retrochorial hematoma
Pathology is asymptomatic in 16-30% of cases. The remaining patients have spotting bloody discharge from the genital tract, separation of blood clots or bleeding. Scanty brown-beige discharge indicates the organization of a hematoma. Cramping pains in the lower abdomen are considered a frequent symptom. Pain syndrome is usually accompanied by corporeal hematomas, bloody discharge – supracervical. The general state of health remains unchanged. The release of scarlet fresh blood from the vagina, increased pain and deterioration of well–being are often signs of an incipient abortion – a condition requiring urgent hospitalization.
The most unfavorable outcomes of pathology are spontaneous abortion (in 9-18% of cases) and frozen pregnancy (1-2%). A hematoma, especially a large one, accompanied by bloody discharge, often becomes a harbinger of future complications. Retrochorial hematoma increases the risk of premature birth by 3.5 times at 22-27 weeks of gestation and twice after 28 weeks. The probability of placental abruption increases 2-2.5 times, preeclampsia – 4 times. There are also risks for the fetus – infants of mothers who suffered a hematoma at the beginning of pregnancy are 2.6 times more likely to experience intrauterine development delay, distress syndrome.
Diagnostic measures are carried out by an obstetrician-gynecologist. Intrauterine hematoma is differentiated with the threat of miscarriage caused by other causes, ectopic pregnancy, cystic drift, tumors of the cervix and uterine body. An important step is to find out the cause of the pathology. The diagnosis is established on the basis of data from the following studies:
- Clinical examination. According to the results of the patient’s survey and general examination, the doctor diagnoses pregnancy (if the patient has not been previously registered), and may suspect a hematoma based on subjective signs. During gynecological examination, the stage of a possible abortion is determined by the state of the cervix and the intensity of bleeding (if any).
- Ultrasonography. A hematoma is determined during ultrasound of the uterus as a sickle-shaped hypo- or anechoic formation occupying part of the circumference of the fetal egg. To choose the treatment tactics, the viability of the embryo is assessed by the presence of a heartbeat. Echography has prognostic value: unfavorable factors of spontaneous abortion are the large size of the hematoma, its corporeal location, a progressive increase in vascular resistance in the chorial tissue and spiral arteries, signs of delayed embryo development, violation of its cardiac activity.
- Determining the cause of hemorrhage is difficult. For this purpose, bacterial examination of the vaginal smear, diagnostic hormonal tests (the level of estrogens and progestins, chorionic gonadotropin, placental lactogen, trophoblastic hormone), PCR analysis for viral infections, coagulogram, analysis for antibodies to chorionic gonadotropin and phospholipids, typing of HLA class II genes are carried out. Prescribe consultations of an immunologist, hematologist and medical geneticist. Nevertheless, it is not always possible to clarify the etiology.
Treatment of retrochorial hematoma
Conservative treatment is carried out on an outpatient basis or in a hospital (with bleeding) by an obstetrician-gynecologist. If the embryo is viable, therapy is aimed at preserving and prolonging gestation, in case of its death, an artificial termination of pregnancy is performed. Chorion detachment is regarded as a threatening abortion. To prevent further separation and expulsion of the fetal egg, rest (including sexual), etiotropic treatment is prescribed:
- Hemostatic therapy. To stop bleeding, tranexamic acid is used, a remedy that has both hemostatic and anti-inflammatory effects, the use of which does not lead to pronounced changes in the hemostasis system.
- Hormone therapy. Natural micronized progesterone acts in several directions at once, providing immunomodulatory and anti-inflammatory effects, reducing the tone of the uterus. In addition, the drug effectively prevents further outpouring of blood after hemostasis.
Symptomatic treatment includes enzyme therapy to accelerate hematoma resorption. Sedatives, antispasmodics and physiotherapy (electrical relaxation of the uterus, magnesium electrophoresis, acupuncture) are prescribed to reduce the tone of the uterus. Special attention is paid to the fight against constipation. Pathogenetic treatment depends on the causes that caused the pathology (for example, with verified immune thrombophilia, antiplatelet agents and glucocorticoids are administered).
Prognosis and prevention
The prognosis of the preservation and successful completion of pregnancy with retrochorial hematoma largely depends on the possibility of identifying and eliminating the causes of pathology, timely initiation of treatment. The most important aspect of primary prevention is pre–pregnancy preparation – a comprehensive examination of spouses and correction of detected violations a few months before the planned pregnancy. Other measures include the avoidance of artificial abortions, household and occupational hazards, a balanced diet and vitamin intake, a rational work and rest regime. Secondary prevention consists in constant obstetric monitoring.