Introduction
All over the world, postpartum hemorrhage is the leading cause of maternal death during childbirth (Brwonlee, 2006). When the uterus fails to contract after a baby is delivered, the site where the placenta detached can bleed excessively. The detachment of the placenta can become more complicated in the case of abruption placentae.
Abruptio Placentae is defined as the separation of a normally implanted placenta from the twentieth week of pregnancy. It is the premature separation of a normally implanted placenta from the uterus. All degrees of placental separation from a few millimeters to complete detachment may occur. The causes are known in a minority of cases; they include hypertensive disorders, trauma, reduction in size of the uterus, pressure on veins draining the uterus, and minor predisposing factors (such as low socioeconomic status and advanced parity). The condition is less common nowadays (Mansfield, 1986).
Both mother and infant are at risk from this condition. Hemorrhage or shock places the mother at greater risk, while prematurity, hypoxia, and respiratory distress syndrome endanger the infant. The perinatal mortality rate is about 30 percent. However, the prognosis depends on prenatal care, since the abruption is likely to be more severe if hypertension, preeclampsia, or anemia is uncontrolled (Mansfield, 1986).
The placenta acts as a life support machine for the baby, which allows oxygen and nutrients to travel across to the baby, while waste products return to mother. But even a small disruption in the contact area between the placenta and womb can lead to torrential bleeding and risks the life of the mother and the baby. To understand the medical condition of Abruptio Placentae, it is best to first understand the placenta first.
Developmental and Physiologic Anatomy of the Placenta
The placenta is the “fetal lung”. Its maternal portion is in effect a large blood sinus. At the 16th day after fertilization, blood begins to be pumped by the heart of the embryo itself in the pregnant woman. Simultaneously, blood sinuses supplied with blood from the mother develop. More projections are made, ultimately creating the placental villi. The blood of the fetus flows through two umbilical arteries, then into the capillaries of the villi, and finally back through a single umbilical vein into the fetus. At the same time, the mother’s blood flows from her uterine arteries into large maternal sinuses that surround the villi and then back into the uterine veins of the mother (Guyton & Hall, 2000).
The total surface area of all the villi of the mature placenta is only a few square meters – many times less than the area of the pulmonary membrane in the lungs. This makes the exchange less efficient (Ganong, 2001). Nevertheless, nutrients and other substances pass through this placental membrane mainly by diffusion in much the same manner that diffusion occurs through the alveolar membranes of the lungs and the capillary membranes elsewhere in the body (Guyton & Hall, 2000).
Placental Permeability and Membrane Diffusion
The major function of the placenta is to provide for diffusion of foodstuffs and oxygen from the mother’s blood into the fetus’ blood and diffusion of excretory products from the fetus back to the mother (Guyton & Hall, 2000). Therefore, the permeability and total membrane diffusion conductance of the placental membrane is a necessary knowledge.
In the early months of pregnancy, the placental membrane is still thick because it is not fully developed. Therefore, its permeability is low. Furthermore, the surface area is slight because the placenta has not grown significantly. Therefore, the total diffusion conductance is miniscule at first. Conversely, in later pregnancy, the permeability increases because of thinning of the membrane diffusion layers and because the surface area becomes many times expanded by growth, thus giving the tremendous increase in placental diffusion (Ganong, 2001).
The placenta produces essential hormones that help maintain the pregnancy. Because the placenta is extremely porous, noxious materials such as viruses and drugs can also pass from mother to child. The effect of noxious agents to the unborn child depends on the developmental stage in which the exposure takes place, with the embryonic stage being the most crucial.
Etiology
Research into the mechanisms which are responsible for abruptio placentae suggest that defects within the methionine-homocysteine metabolic pathway and folate deficiency increase the risk of abruptio placentae and other placental vascular disease. A possible biologic mechanism to explain the increased risks found for abruptio placentae and exposure to chlorination by-products may be the effect on methioinine-homocysteine or folate metabolism (Allen, et al, 2000).
Blunt force directed to the uterus can cause abruptio placentae or uterine rupture. Abruptio placentae is estimated to occur in 40 to 50 percent of patients with major traumatic injuries and in up to 5 percent of patients with minor injuries. The uterus is relatively elastic compared with the placenta, and force directed to the uterus can cause shearing of the "inelastic" placenta, producing placental abruption or uterine rupture. The extensive blood loss that ensues may compromise or kill the fetus, and the extent of uterine damage may make repair impossible, necessitating emergency hysterectomy (Lense, 1996).
Abruption of the placenta also occurs in association with placenta previa. Cesarean section causes scarring of the uterine wall, with the result that placentation may not be optimal. That's why it may be leading to abruption. In a study among 40,472 women whose first delivery was by cesarean section, the relative risk of placental abruption was 1.3 in the second pregnancy, compared with women whose first delivery was vaginal (Johnson, 2006).
Additionally, pharmacological actions of cocaine are consistent with the temporal association between cocaine use and the occurrence of abruptio placentae as well as the association of cocaine use with the onset of uterine contractions and labor. The consequences of abruptio placentae and pre-term labor are prematurity and its attendant complications (Gardner, 1991). There are disturbing reports showing that the use of aspirin increases the chance of abruptio placentae.
Symptoms and Signs of Abruptio Placentae
As is already mentioned, abruptio placentae is the premature separation of a normally implanted placenta from the uterus. The figure below shows this condition:
Source: Merck Manual
Placental abruptions usually occur from 16 weeks of gestation onward. Some signs of placental abruption, including spontaneous rupture of membranes, vaginal bleeding, and uterine tenderness, are infrequent after trauma. Although associated with maternal and fetal morbidity, these signs are only 52 percent sensitive and 48 percent specific for adverse fetal outcomes (Grossman, 2004).
Retroplacental bleeding occurs, and the blood may pass behind the membranes and through the cervix (external hemorrhage) or can be retained behind the placenta (concealed hemorrhage). Symptoms and signs depend on the degree of separation and blood loss. In severe cases, they include vaginal bleeding, a tender and tightly contracted uterus, evidence of fetal cardiac distress or death, and maternal shock. Serious complications, particularly with preexisting toxemia, include hypofibrinogenemia with disseminated intravascular coagulation (DIC), acute renal failure, and uteroplacental apoplexy (Couvelaire uterus).
Treatment
Evaluating placental completeness is of critical, immediate importance in the delivery room. Retained placental tissue is associated with postpartum hemorrhage and infection. Blood may be adherent to the maternal surface of the placenta, particularly at or near the margin. If the blood is rather firmly attached, and especially if it distorts the placenta, it may represent an abruption. Clots on the maternal surface, particularly adherent centrally located dots, may represent placental abruption. It should be emphasized, however, that abruption is a clinical diagnosis (Yetter, 1998).
Continuous electronic fetal monitoring after trauma is the current standard of care with a viable fetus. Monitoring is initiated as soon as possible after maternal stabilization, because most placental abruptions occur shortly after trauma. Occasional uterine contractions are the most common finding after trauma in pregnant women. These occasional contractions are not associated with adverse fetal outcomes and resolve within a few hours in 90 percent of cases. The occurrence of eight or more uterine contractions per hour for more than four hours, however, is associated with placental abruption or abruptio placentae (Grossman, 2004).
Continuous electronic fetal monitoring is more sensitive in detecting placental disruption than ultrasonography, intermittent monitoring, an acid elution test (Kleihauer-Betke test to assess the amount of fetal blood in the maternal serum), or physical examination. However, continuous fetal monitoring prevents few perinatal deaths. It is most useful for determining reassuring fetal status and appropriate discharge. Abnormal tracings are not reliable in predicting adverse fetal outcomes. In contrast, a normal tracing has a negative predictive value of 100 percent when combined with a normal physical examination (Grossman, 2004).
If the patient’s bleeding is not life-threatening, if the fetal tones are normal, and if the pregnancy is not near term, bed rest is advisable, with hope that the bleeding will lessen. If the condition improves, ambulation may be allowed, and the patient may even be discharged if there is no further bleeding and she has easy access to the hospital. If the bleeding continues or worsens, delivery is indicated in both fetal and maternal interests.
When abruptio placentae cannot be distinguished from placenta previa without vaginal examination, such an examination must be performed just before delivery; however, unless delivery is to be immediate, vaginal examination is contraindicated. If the placenta can be located by ultrasound, the double set-up examination should be performed in an operating room prepared for both cesarean section and vaginal delivery. Instruments and staff for both procedures should be ready. The cervix is gently examined to determine whether the placenta is on or near it. If it is not, amniotomy should be performed and, if the cervix is ripe and favorable for vaginal delivery, a dilute infusion of oxytocin is begun. Amniotomy seems to lessen the incidence of hypofibrinogenemia as a complication. If the cervix is not ripe, cesarean section should be performed (Merck Manual, 2006).
Case Scenarios
Abruptio placentae, with the symptoms of hemorrhage, pallor, fainting, weak pulse with some external hemorrhage as well, present a very bad prognosis for both mother and child. In one case, the mother at the hospital had a normal delivery. However, the placenta showed that it had been partially detached but the child was normal and is now almost one year of age.
Unfortunately, twenty hours after delivery, the mother suddenly showed marked dyspnea, and pulmonary edema developed rapidly, with fear of impending death and marked cyanosis. The mother died. The patient was perfectly conscious until three minutes before death, but there was the awful air-hunger and progressing degree of cyanosis. Suddenly the click of an edematous glottis closed the tragedy: The lungs were profoundly edematous, because of pulmonary thrombosis (Hemingway, 1999).
When the famous singer and actress Madonna gave birth to her son Rocco, she also suffered abruptio placentae. Doctors discovered she had a detached placenta, cutting off the baby's oxygen supply.
Prevention and Health Promotion
Thoughts of delivering a healthy baby are foremost in a mother’s mind as she focuses on preparing her body and mind for the delivery. When complications arises, such as during abruption placentae, the mother needs all the help and support she can get.
Round-the-clock surveilance and treatment by hospital staff specially trained in intensive care for newborns is a must in giving high-risk newborns their best chance for survival. There are some hospitals that have established separate nurseries, often called neonatal (newborn) intensive-care units, that are staffed by neonatologists, respiratory therapists, technicians, nurses, and possibly even social workers, in order to provide care for these newborns at risk. If a doctor thinks that a baby may be at increased risk of neonatal complications, arrangements may be made for transfer and delivery at a hospital that includes an intensive-care nursery if the hospital where the mother is admitted does not have one. Another option may be that a baby is transferred from another hospital in a specially equipped ambulance. Along the way to the other hospital, care is provided by medical personnel who have the knowledge on how to keep the baby's condition stabilized (Farley, 1985).
The pregnant mother needs information regarding the birthing process and ay complications that might occur. Health care professionals can make a significant difference in supporting and reassuring mothers during the course of childbirth.
All over the world, postpartum hemorrhage is the leading cause of maternal death during childbirth (Brwonlee, 2006). When the uterus fails to contract after a baby is delivered, the site where the placenta detached can bleed excessively. The detachment of the placenta can become more complicated in the case of abruption placentae.
Abruptio Placentae is defined as the separation of a normally implanted placenta from the twentieth week of pregnancy. It is the premature separation of a normally implanted placenta from the uterus. All degrees of placental separation from a few millimeters to complete detachment may occur. The causes are known in a minority of cases; they include hypertensive disorders, trauma, reduction in size of the uterus, pressure on veins draining the uterus, and minor predisposing factors (such as low socioeconomic status and advanced parity). The condition is less common nowadays (Mansfield, 1986).
Both mother and infant are at risk from this condition. Hemorrhage or shock places the mother at greater risk, while prematurity, hypoxia, and respiratory distress syndrome endanger the infant. The perinatal mortality rate is about 30 percent. However, the prognosis depends on prenatal care, since the abruption is likely to be more severe if hypertension, preeclampsia, or anemia is uncontrolled (Mansfield, 1986).
The placenta acts as a life support machine for the baby, which allows oxygen and nutrients to travel across to the baby, while waste products return to mother. But even a small disruption in the contact area between the placenta and womb can lead to torrential bleeding and risks the life of the mother and the baby. To understand the medical condition of Abruptio Placentae, it is best to first understand the placenta first.
Developmental and Physiologic Anatomy of the Placenta
The placenta is the “fetal lung”. Its maternal portion is in effect a large blood sinus. At the 16th day after fertilization, blood begins to be pumped by the heart of the embryo itself in the pregnant woman. Simultaneously, blood sinuses supplied with blood from the mother develop. More projections are made, ultimately creating the placental villi. The blood of the fetus flows through two umbilical arteries, then into the capillaries of the villi, and finally back through a single umbilical vein into the fetus. At the same time, the mother’s blood flows from her uterine arteries into large maternal sinuses that surround the villi and then back into the uterine veins of the mother (Guyton & Hall, 2000).
The total surface area of all the villi of the mature placenta is only a few square meters – many times less than the area of the pulmonary membrane in the lungs. This makes the exchange less efficient (Ganong, 2001). Nevertheless, nutrients and other substances pass through this placental membrane mainly by diffusion in much the same manner that diffusion occurs through the alveolar membranes of the lungs and the capillary membranes elsewhere in the body (Guyton & Hall, 2000).
Placental Permeability and Membrane Diffusion
The major function of the placenta is to provide for diffusion of foodstuffs and oxygen from the mother’s blood into the fetus’ blood and diffusion of excretory products from the fetus back to the mother (Guyton & Hall, 2000). Therefore, the permeability and total membrane diffusion conductance of the placental membrane is a necessary knowledge.
In the early months of pregnancy, the placental membrane is still thick because it is not fully developed. Therefore, its permeability is low. Furthermore, the surface area is slight because the placenta has not grown significantly. Therefore, the total diffusion conductance is miniscule at first. Conversely, in later pregnancy, the permeability increases because of thinning of the membrane diffusion layers and because the surface area becomes many times expanded by growth, thus giving the tremendous increase in placental diffusion (Ganong, 2001).
The placenta produces essential hormones that help maintain the pregnancy. Because the placenta is extremely porous, noxious materials such as viruses and drugs can also pass from mother to child. The effect of noxious agents to the unborn child depends on the developmental stage in which the exposure takes place, with the embryonic stage being the most crucial.
Etiology
Research into the mechanisms which are responsible for abruptio placentae suggest that defects within the methionine-homocysteine metabolic pathway and folate deficiency increase the risk of abruptio placentae and other placental vascular disease. A possible biologic mechanism to explain the increased risks found for abruptio placentae and exposure to chlorination by-products may be the effect on methioinine-homocysteine or folate metabolism (Allen, et al, 2000).
Blunt force directed to the uterus can cause abruptio placentae or uterine rupture. Abruptio placentae is estimated to occur in 40 to 50 percent of patients with major traumatic injuries and in up to 5 percent of patients with minor injuries. The uterus is relatively elastic compared with the placenta, and force directed to the uterus can cause shearing of the "inelastic" placenta, producing placental abruption or uterine rupture. The extensive blood loss that ensues may compromise or kill the fetus, and the extent of uterine damage may make repair impossible, necessitating emergency hysterectomy (Lense, 1996).
Abruption of the placenta also occurs in association with placenta previa. Cesarean section causes scarring of the uterine wall, with the result that placentation may not be optimal. That's why it may be leading to abruption. In a study among 40,472 women whose first delivery was by cesarean section, the relative risk of placental abruption was 1.3 in the second pregnancy, compared with women whose first delivery was vaginal (Johnson, 2006).
Additionally, pharmacological actions of cocaine are consistent with the temporal association between cocaine use and the occurrence of abruptio placentae as well as the association of cocaine use with the onset of uterine contractions and labor. The consequences of abruptio placentae and pre-term labor are prematurity and its attendant complications (Gardner, 1991). There are disturbing reports showing that the use of aspirin increases the chance of abruptio placentae.
Symptoms and Signs of Abruptio Placentae
As is already mentioned, abruptio placentae is the premature separation of a normally implanted placenta from the uterus. The figure below shows this condition:
Source: Merck Manual
Placental abruptions usually occur from 16 weeks of gestation onward. Some signs of placental abruption, including spontaneous rupture of membranes, vaginal bleeding, and uterine tenderness, are infrequent after trauma. Although associated with maternal and fetal morbidity, these signs are only 52 percent sensitive and 48 percent specific for adverse fetal outcomes (Grossman, 2004).
Retroplacental bleeding occurs, and the blood may pass behind the membranes and through the cervix (external hemorrhage) or can be retained behind the placenta (concealed hemorrhage). Symptoms and signs depend on the degree of separation and blood loss. In severe cases, they include vaginal bleeding, a tender and tightly contracted uterus, evidence of fetal cardiac distress or death, and maternal shock. Serious complications, particularly with preexisting toxemia, include hypofibrinogenemia with disseminated intravascular coagulation (DIC), acute renal failure, and uteroplacental apoplexy (Couvelaire uterus).
Treatment
Evaluating placental completeness is of critical, immediate importance in the delivery room. Retained placental tissue is associated with postpartum hemorrhage and infection. Blood may be adherent to the maternal surface of the placenta, particularly at or near the margin. If the blood is rather firmly attached, and especially if it distorts the placenta, it may represent an abruption. Clots on the maternal surface, particularly adherent centrally located dots, may represent placental abruption. It should be emphasized, however, that abruption is a clinical diagnosis (Yetter, 1998).
Continuous electronic fetal monitoring after trauma is the current standard of care with a viable fetus. Monitoring is initiated as soon as possible after maternal stabilization, because most placental abruptions occur shortly after trauma. Occasional uterine contractions are the most common finding after trauma in pregnant women. These occasional contractions are not associated with adverse fetal outcomes and resolve within a few hours in 90 percent of cases. The occurrence of eight or more uterine contractions per hour for more than four hours, however, is associated with placental abruption or abruptio placentae (Grossman, 2004).
Continuous electronic fetal monitoring is more sensitive in detecting placental disruption than ultrasonography, intermittent monitoring, an acid elution test (Kleihauer-Betke test to assess the amount of fetal blood in the maternal serum), or physical examination. However, continuous fetal monitoring prevents few perinatal deaths. It is most useful for determining reassuring fetal status and appropriate discharge. Abnormal tracings are not reliable in predicting adverse fetal outcomes. In contrast, a normal tracing has a negative predictive value of 100 percent when combined with a normal physical examination (Grossman, 2004).
If the patient’s bleeding is not life-threatening, if the fetal tones are normal, and if the pregnancy is not near term, bed rest is advisable, with hope that the bleeding will lessen. If the condition improves, ambulation may be allowed, and the patient may even be discharged if there is no further bleeding and she has easy access to the hospital. If the bleeding continues or worsens, delivery is indicated in both fetal and maternal interests.
When abruptio placentae cannot be distinguished from placenta previa without vaginal examination, such an examination must be performed just before delivery; however, unless delivery is to be immediate, vaginal examination is contraindicated. If the placenta can be located by ultrasound, the double set-up examination should be performed in an operating room prepared for both cesarean section and vaginal delivery. Instruments and staff for both procedures should be ready. The cervix is gently examined to determine whether the placenta is on or near it. If it is not, amniotomy should be performed and, if the cervix is ripe and favorable for vaginal delivery, a dilute infusion of oxytocin is begun. Amniotomy seems to lessen the incidence of hypofibrinogenemia as a complication. If the cervix is not ripe, cesarean section should be performed (Merck Manual, 2006).
Case Scenarios
Abruptio placentae, with the symptoms of hemorrhage, pallor, fainting, weak pulse with some external hemorrhage as well, present a very bad prognosis for both mother and child. In one case, the mother at the hospital had a normal delivery. However, the placenta showed that it had been partially detached but the child was normal and is now almost one year of age.
Unfortunately, twenty hours after delivery, the mother suddenly showed marked dyspnea, and pulmonary edema developed rapidly, with fear of impending death and marked cyanosis. The mother died. The patient was perfectly conscious until three minutes before death, but there was the awful air-hunger and progressing degree of cyanosis. Suddenly the click of an edematous glottis closed the tragedy: The lungs were profoundly edematous, because of pulmonary thrombosis (Hemingway, 1999).
When the famous singer and actress Madonna gave birth to her son Rocco, she also suffered abruptio placentae. Doctors discovered she had a detached placenta, cutting off the baby's oxygen supply.
Prevention and Health Promotion
Thoughts of delivering a healthy baby are foremost in a mother’s mind as she focuses on preparing her body and mind for the delivery. When complications arises, such as during abruption placentae, the mother needs all the help and support she can get.
Round-the-clock surveilance and treatment by hospital staff specially trained in intensive care for newborns is a must in giving high-risk newborns their best chance for survival. There are some hospitals that have established separate nurseries, often called neonatal (newborn) intensive-care units, that are staffed by neonatologists, respiratory therapists, technicians, nurses, and possibly even social workers, in order to provide care for these newborns at risk. If a doctor thinks that a baby may be at increased risk of neonatal complications, arrangements may be made for transfer and delivery at a hospital that includes an intensive-care nursery if the hospital where the mother is admitted does not have one. Another option may be that a baby is transferred from another hospital in a specially equipped ambulance. Along the way to the other hospital, care is provided by medical personnel who have the knowledge on how to keep the baby's condition stabilized (Farley, 1985).
The pregnant mother needs information regarding the birthing process and ay complications that might occur. Health care professionals can make a significant difference in supporting and reassuring mothers during the course of childbirth.
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