Risk
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Occurs in 0.4-1% of pregnancies, and the incidence is increasing, particularly among African Americans.
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Associated with the following conditions: preeclampsia, hypertension, chorioamnionitis, cocaine use, alcohol use, trauma, increased age and parity, smoking, premature rupture of membranes, prior abruption, and multiple gestation.
Perioperative Risks
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Maternal: Antepartum and postpartum hemorrhage, DIC, and death.
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Fetal: Hypoxia, prematurity, and fetal demise. Placental separation may lead to reduced gas exchange surface area, and maternal hypotension will worsen uteroplacental blood flow.
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Maternal risk lies in severity of abruption, whereas fetal risk depends on both severity and gestational age at time of abruption.
Perioperative Risks
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Maternal: Antepartum and postpartum hemorrhage, DIC, and death.
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Fetal: Hypoxia, prematurity, and fetal demise. Placental separation may lead to reduced gas exchange surface area, and maternal hypotension will worsen uteroplacental blood flow.
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Maternal risk lies in severity of abruption, whereas fetal risk depends on both severity and gestational age at time of abruption.
Worry About
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Concealed hemorrhage in a retroplacental hematoma may not manifest as vaginal bleeding and can lead to considerable underestimation of maternal hypovolemia.
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Postpartum hemorrhage refractory to usual oxytocic agents; some believe old blood can infiltrate into and between uterine muscle fibers and decrease the effectiveness of uterine contractions (Couvelaire uterus). May need peripartum hysterectomy as a last resort.
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Maternal coagulopathy occurs in 10% of cases.
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Fetal distress and demise.
Overview
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Along with placenta previa, a major cause of antepartum hemorrhage, maternal mortality, and perinatal mortality.
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Perinatal mortality is 12%, but it varies depending on severity of abruption and gestational age.
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Classical clinical triad of metrorrhagia, uterine hypertonia, and abdominopelvic pains presents in only 9.7% of cases.
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Placental abruption is the most common condition (37%) associated with DIC in obstetric pts. DIC is probably because of the release of thromboplastin into the central circulation by placental tissues at abruption site.
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Postpartum hemorrhage correlates directly with severity of coagulopathy.
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Blood and blood clots in muscle fibers may inhibit ability of uterus to contract, which leads to more blood loss.
Usual Treatment
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Meticulous attention to maternal volume status and fetal surveillance.
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Timing and route of delivery depend on degree of maternal and fetal compromise and estimated gestational age.
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If fetus is preterm and both maternal/fetal status are reassuring, careful observation to optimize fetal maturation is appropriate.
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If fetus is at or near term and both maternal/fetal status are reassuring, vaginal delivery is reasonable.
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If maternal or fetal status is nonreassuring, cesarean delivery is necessary. Cesarean delivery rates are as high as 90%, with 51% being performed under general anesthesia.
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If fetus demise occurs and mother is stable, then vaginal delivery may be considered, if imminent.