Abruptio Placentae Essay
Abstract
Abruptio placentae is a partial or total detachment of a normally implanted placenta from the uterine wall during pregnancy or delivery. The current statistical data testify to the significance of this health care issue. The incidence of placental abruption is associated with high rates of maternal and perinatal morbidity and mortality globally. Hysterectomy, sepsis, cesarean deliveries, hemorrhagic shock, uterine rupture, anemia, pulmonary edema, and other disorders are the most frequent complications of the abruption in women. Adverse perinatal outcomes include congenital malformations, vasa previa, fetal distress, low APGAR scores, and perinatal deaths. The review of pertinent scholarly publications allowed specifying the main predisposing risk factors for abruptio placentae. Vascular, haemostatic, physiological, and mechanical etiological factors can cause abruptio placentae. However, their interrelations appear to be underinvestigated. Bleeding is identified as a basic symptom of placental abruption. Its severity depends on blood hemostatic properties. Early diagnostics is a determinative in the prevention and treatment of this condition. Specific curative methods are applied in accordance with the severity of placental abruption, hemostasis, the volume of blood loss, maternal and fetal health conditions, and gestational age.
Keywords: abruptio placentae, placental abruption, bleeding, disseminated intravascular coagulation (DIC), maternal and perinatal morbidity and mortality
Abruptio Placentae
Abruptio placentae is one of the most threatening complications of pregnancy and delivery, which often leads to severe consequences for both a mother and fetus. It is identified as a partial or total detachment of a normally implanted placenta from the uterine wall during pregnancy or delivery (Pariente et al., 2011, p. 698). Achievements in obstetric science and practice, diagnostics, anesthesiology, and intensive care have greatly contributed to the solution of this issue. However, despite advancements in health care, placental abruption is one of the major causes of maternal mortality, involving hemorrhage, thromboembolic complications, disseminated intravascular coagulation (DIC), post-hemorrhagic anemia, respiratory and renal failure, and hypertensive disorders (Tikkanen et al., 2013, p. 298). Moreover, its occurrence still results in high rates of perinatal mortality and birth of children in a critical condition of severe birth asphyxia.
The Occurrence of Abruptio Placentae
There is a growing concern about the incidence of abruptio placentae both nationwide and globally due to its increasing occurrence. In order to reduce current rates of this phenomenon, the recent studies have been conducted by Pariente et al. (2011), Tikkanen et al. ( 2013), Mukherjee, Bawa, Sharma, Nandanwar, and Gadam (2014), and Chhabra, Pandit, and Gosavi (2014). They have systematically examined long-term trends of placental abruption specific to different nations. According to their findings, abruptio placentae occurs in approximately 1 in 100 to 200 (0.5–1%) pregnancies in developed nations, such as the United States, Norway, Israel, Finland, and others (Elsasser, Ananth, Prasad, & Vintzileos, 2010; Pariente et al., 2011; Tikkanen et al., 2013; Chhabra et al., 2014; Mukherjee et al., 2014). Abruptio placentae occurs more frequently in nulliparous women. Mukherjee et al. claim that the rates of placental abruption are significantly higher in developing countries, comprising roughly 4.5%. The studies under scrutiny define abruptio placentae as a dominant cause of maternal and perinatal mortality despite its rarity. It results in about 15% of maternal mortality (Chhabra et al., 2014, p. 604). In accordance with the statistical evidence provided by Tikkanen et al. (2013), “placental abruption explained 7% of all perinatal mortality” (p. 298). These numerical data testify the importance of this health care issue. However, those cases of placental abruption are usually taken into considerations which have been clearly diagnosed. In fact, this pathology occurs much more often, especially at the spontaneous premature termination of pregnancy at the early and late stages.
Etiology of Abruptio Placentae
The extensive epidemiological and clinical research has not exhaustively elucidated causes of abruptio placentae yet (Elsasser et al., 2010; Pariente et al., 2011; Tikkanen et al., 2013; Chhabra et al., 2014; Mukherjee et al., 2014). The root cause of the abruption of normally located placenta is not always possible to determine. The etiology of this phenomenon is multifactorial. Vascular, haemostatic, physiological, and mechanical conditions can cause abruptio placentae. Emphasizing the role of vasculopathy in the development of this obstetrical disorder, Elsasser et al. (2010) state the following. Placental abruption is “the consequence of abnormal trophoblast invasion leading to rupture of the spiral arteries and premature separation of the placenta” (p. 126). In accordance with the recent research findings, predisposing risk factors for abruptio placentae can be divided into the following groups: 1) pathological conditions and diseases preceding pregnancy, which directly contribute to the emergence and development of placental abruption (underlying predisposing diseases); 2) disorders that develop across pregnancy and delivery, leading to this obstetrical condition in parturient women. Although risk factors from both groups are interrelated and “a vast majority of placental abruption cases appears to have a long-standing chronic etiology” (Elsasser et al., 2010, p. 131), the concordance between them appears to be understudied.
Such disorders as diabetes mellitus, various cardiac anomalies, Rh factor incompatibility, genitourinary diseases (glomerulonephritis, pyelonephritis, and others), and antiphospholipid syndrome are among the causes that trigger the appearance and development of placental abruption. Also, such factors may include as: fibrin deposition, villous maldevelopment, diseases of the blood and connective tissue (systemic lupus erythematosus), dysfunctions of thyroid, inflammatory diseases and tumors (fibroids) of the uterus, previous serious operations and Caesarean Section (CS), allergic responses, genetic defects of hemostasis predisposing to thrombosis, and hypertension (Elsasser et al., 2010; Pariente et al., 2011; Tikkanen et al., 2013; Chhabra et al., 2014; Mukherjee et al., 2014). Advanced maternal age, offspring sex, maternal cigarette smoking, substance abuse, alcohol consumption, low prepregnancy body mass index, and previous spontaneous abortions are also associated with placental abruption. They can be identified as underlying etiologic factors (Tikkanen et al., 2013, p. 299; Chhabra et al., 2014, p. 605; Mukherjee et al., 2014, p. 425).
Developing across pregnancy and delivery, vascular disorders of the utero-placental complex are the main predisposing factors of abruptio placentae (Elsasser et al., 2010). These causes lead to broken links between the placenta and the uterine wall and vessel rupture with the formation of hemorrhage (retroplacental hematoma). In accordance with the research findings provided by Mukherjee et al. (2014), gestational hypertension is a leading obstetric risk factor of placental abruption, totaling approximately 15% of cases (p.426). Chhabra et al. (2014) identify that anaemia is observed in 51.87% (p. 605). Other risk factors of this group include eclampsia, preeclampsia, short umbilical cord, chorioamnionitis, funisitis, oligoamnios, hyperextension of the uterus walls, intrauterine growth restriction (IUGR), and intrauterine infections (Elsasser et al., 2010; Pariente et al., 2011; Chhabra et al., 2014). The overdistension of the uterus triggered by polyhydramnios, multiple pregnancy, large fetus, and so forth predisposes to the development of placental abruption as well. Abdominal traumas are also associated with abruptio placentae (Chhabra et al., 2014; Mukherjee et al., 2014). Car accidents are the most dangerous situations. In some cases, seat belts cause abdominal traumas, abruptly hitting the body.
Symptoms and Pathophysiology of Abruptio Placentae
Depending on the severity of the abruption, the most prevalent manifestations of abruptio placentae include painful vaginal bleeding, severe abdominal and uterine pain, abnormal uterine contractions or uterine hyper tonicity, tenderness, maternal hemodynamic instability, retroplacental bleeding or clot(s), and fetal distress (Elsasser et al., 2010, p. 127; Mukherjee et al., 2014, p. 426). Bleeding may be internal (retroplacental hematoma) and external. The degree of it depends on hemostatic properties of blood and the location and area of placental abruption. Abdominal pain is caused by stretching of the uterine, imbibition of its walls with blood, or peritoneal irritation. Uterine hyper tonicity is associated with internal bleeding and the presence of retroplacental hematoma, blood imbibition, and overstretching of the uterus walls. In response to constant irritants, the uterus wall contracts. Women’s weakness, dizziness, and vomiting are observed. Skin and visible mucous membranes are pale. Arterial blood pressure reduces; hemodynamic abnormalities develop when the volume of retroplacental hematoma reaches 300 ml.
Placental abruption begins with hemorrhage in the decidua basalis, causing damage to all layers of the decidua with its detachment from the muscle layer of the uterus. Due to the growing rupture of blood vessels, a hematoma is formed, leading to the separation, compression, and destruction of the placenta adjacent to the site. The area of placental abruption can increase rapidly. The uterus stretches due to the growth of hematoma. A contractile ability of the myometrium decreases, resulting in broken blood vessels in the site of placental abruption and prolonged bleeding. Accumulating, blood detaches layers from the uterine wall and flows out from the genital tract. If blood does not leak away, it can accumulate between the uterus walls and placenta as a hematoma. It penetrates the placenta and myometrium, causing the superdistension of the uterine walls. This tension can be so significant that micro fissures develop in the uterine walls and serous membrane. The uterus is impregnated with blood (Couvelaire uterus or uteroplacental apoplexy). If the site of placental abruption is insignificant, after the formation of retroplacental hematoma, thrombosis of uterine vessels on the background of villi compression is possible. Further placental abruption stops. At the site of detachment, infarctions and salt deposits are formed. Those ones can be observed after delivery.
As a result of the myometrium destruction and retroplacental clotting, a large amount of prothrombinase is released in the maternal circulation. In severe cases, disseminated intravascular coagulation (DIC) develops due to fibrin deposition. Fibrinogen deficiency in peripheral blood causes hypofibrinogenemia accompanied by significant bleeding from the uterus and other organs. If the site of placental abruption is small, pregnancy and delivery can proceed normally. However, if the detachment occupies more than 1/3 of the surface of the placenta and retroplacental hematoma is 500 ml or more, the fetus usually dies from hypoxia and asphyxia. It may be triggered by impaired uteroplacental circulation. Moreover, being separated, the placenta is not able to exchange gases and provide the fetus with necessary nutrients. Thus, the abruption of the placenta leads to numerous adverse perinatal outcomes, such as vasa previa, congenital malformations, fetal distress, “low APGAR scores at 1 and 5 min <7”, and perinatal deaths (Pariente et al., 2011, p. 699; Tikkanen et al., 2013, p. 303; Chhabra et al., 2014, p.607). Abruptio placentae is associated with such adverse outcomes for women as hysterectomy, sepsis, cesarean deliveries (Pariente et al., 2011, p. 699), hemorrhagic shock, uterine rupture, anemia, pulmonary edema, atelectasis, severe degenerative and necrotic changes in parenchymal organs, and an acute renal failure. Deliveries are complicated by a pathological preliminary period, untimely amniorrhea, discoordination of labor, and imbalance between the presenting part of the fetus and mother's pelvis.
Diagnostics, Treatment, and Preventive Measures
In order to identify pregnancies with a risk of abruptio placentae, females’ health conditions should be targeted and carefully evaluated (Pariente et al., 2011, p. 671).Early diagnostics is a determinative. The diagnosis of abruptio placentae is primarily based on the assessment of patients’ complaints, anamnesis, clinical presentation, objective research, and specific laboratory tests. It is essential to consider the presence of extragenital disorders, such as hypertension, vascular diseases, diabetes, pyelonephritis, glomerulonephritis, traumas, gestosis, and so forth. The clinical presentation is caused by the degree and location of placental abruption. Diagnostics involves the detection of blood discharge from the genital tract during pregnancy or delivery against the background of hypertonus and asymmetry of the uterus, the abdominal pain combined with signs of increasing hypoxia and asphyxia. Hypotension and frequent, soft, and easily compressible pulse testify to internal bleeding.
If placental abruption occurs at delivery, contractions weaken and become irregular. The uterus does not relax between contractions. At auscultation, increasing hypoxia and asphyxia is characterized by tachycardia replaced by bradycardia and heart rhythm disorder. The variability of the basal rate reduces. Deep and prolonged late decelerations occur; the heart rate incompletely recovers; and a sinusoidal rhythm appears.
Diagnostics can be complicated if there is no external bleeding. It may be hard also if a patient's condition is caused not only by placental abruption but other aggravating circumstances with lesions of vital organs and systems due to preeclampsia, eclampsia, anuria, and impaired respiratory functions. In this case, the clinical picture of these states will dominate over symptoms of abruption placentae. Ultrasound provides substantial assistance in diagnosing placental abruption. It allows determining the location and volume of retroplacental hematoma. In the absence of external bleeding, retroplacental hematoma is visualized as a hypoechoic lesion of various sizes that is located between the wall of the uterus and placenta. According to laboratory tests of hemostasis, the anticoagulation is identified in patients with severe placental abruption due to the consumption of clotting factors. A decrease in the number of platelets, fibrinogen concentration, and a level of antithrombin III is revealed. The microscopic examination defines extensive microinfarcts of the placenta, fibrin thrombi, villi sclerosis, and thinning or absence of the decidual tissue.
The treatment depends on the severity of placental abruption, hemostasis, the volume of blood loss, maternal and fetal health conditions, and gestational age (Tikkanen et al., 2013; Chhabra et al., 2014; Mukherjee et al., 2014, p. 428). In severe conditions of the abruption, irrespectively of gestational age and fetal status, cesarean delivery is able to reduce neonatal mortality. When Couvelaire uterus is diagnosed, the ligation of internal iliac arteries is performed after the delivery. If bleeding stops, the uterus is preserved. Hysterectomy is performed in case of prolonged bleeding. If maternal and fetal conditions are not significantly affected, and there is no expressed external or internal bleeding (small non-progressive retroplacental hematoma), a watchful waiting is recommended at the gestational age of 34-35 weeks. “Maternal and fetal outcome can be optimized through attention to risk and benefits of conservative management versus expeditious delivery in cases of AP” (Mukherjee et al., 2014, p. 428). Management of pregnancy is performed under ultrasound control, with a constant monitoring of the fetus through the utilization of dopplerometry and Cardiocotography. Therapy involves a bed regime and the introduction of b-agonists, antispasmodics, disaggregants, multivitamins, and antianemic drugs. Under indications, the transfusion of blood, fresh frozen plasma, fibrinogen, and platelet concentrate is administered.
There is no specific prevention of placental abruption. Preventive measures include a pre-conceptional preparation, treatment of endometritis and extragenital diseases before pregnancy, an early detection and timely treatment of comorbid diseases, and a correction of revealed abnormalities in hemostasis. Although pregnancy is a normal biological process occurring in women, it requires conscious attitudes to the conception and child bearing. Thus, the promotion of a healthy lifestyle and avoidance of tobacco smoking, excessive alcohol consumption, and substance abuse can significantly reduce predisposing risk factors for abruptio placentae. Pregnant women should know that when blood discharges from the genital tract occur, they must be urgently hospitalized. An interdisciplinary team approach to the treatment of placental abruption can contribute to the reduction of maternal and perinatal mortality and morbidity associated with this disorder.
Conclusion
Abruptio placentae is one of the most threatening complications of pregnancy and delivery, which often leads to grave consequences for both a mother and fetus. So far, placental abruption is one of the major causes of maternal mortality from bleeding during pregnancy. Its development leads to unreasonably high rates of perinatal mortality and birth of children in the state of severe asphyxia. However, the investigation of the etiology of abruptio placentae has revealed the following fact. Predisposing risk factors for this condition are not comprehensively evaluated from a comparative perspective. It remains unknown if genetic predisposition contributes to the occurrence of placental abruption. Thus, the phenomenon of abruptio placentae requires further research studies.
