EPIDEMIOLOGY & DEMOGRAPHICS
RISK FACTORS: Hypertension (greatest association), trauma, polyhydramnios, multifetal gestation, smoking, use of crack cocaine, chorioamnionitis, preterm premature rupture of membranes.
PHYSICAL FINDINGS & CLINICAL PRESENTATION
• Triad of uterine bleeding (concealed or per vagina), hypertonic uterine contractions or signs of preterm labor, and evidence of fetal compromise exists.
• More than 80% of cases have external bleeding; 20% of cases have no bleeding but have indirect evidence of abruption, such as failed tocolysis for preterm labor.
• Tetanic uterine contractions are found in only 17% of cases, unless grade II or III abruption.
Abruptio placentae is the separation of placenta from the uterine wall before delivery of the fetus. There are three classes of abruption based on maternal and fetal status, including an assessment of uterine contractions, quantity of bleeding, fetal heart rate monitoring, and abnormal coagulation studies (fibrinogen, PT, PTT).
• Grade I: mild vaginal bleeding, uterine irritability, stable vital signs, reassuring fetal heart rate, normal coagulation profile (fibrinogen 450 mg %)
• Grade II: Moderate vaginal bleeding, hypertonic uterine contractions, orthostatic blood pressure measurements, unfavorable fetal status, fibrinogen 150 mg % to 250 mg %
• Grade III: severe bleeding (may be concealed), hypertonic uterine contractions, overt signs of hypovolemic shock, fetal death, thrombocytopenia, fibrinogen <150 mg %
• Hypertension: found in 40% to 50% of grade III abruptions
• Rapid decompression of uterine cavity, such as is found with polyhydramnios or multifetal gestation
• Blunt external trauma (motor vehicle accident, spousal abuse)
Placenta previa, cervical or vaginal trauma, labor, cervical cancer, rupture of membranes.
• Initial assessment should evaluate for the source of bleeding, ruling out placenta previa and associated conditions that contraindicate any type of vaginal examination (e.g., pelvic speculum examination).
• Continuous fetal heart monitoring is indicated for all viable gestations (60% incidence of fetal distress in labor); may show early signs of maternal hypovolemia (late decelerations or fetal tachycardia) before overt maternal vital sign changes.
• Actual amount of blood loss is often greater than initially perceived because of the possibility of concealed retroplacental bleeding and the apparent “normal” vital signs. The relative hypervolemia of pregnancy initially protects the gravida until late in the course of bleeding, when abrupt and sudden cardiovascular collapse can occur without warning.
• Baseline Hgb and Hct help quantify blood loss and, even more important, with every four to six determinations can demonstrate significant trends during expectant management.
• Coagulation profile: platelets, fi-brinogen, prothrombin, and partial thromboplastin time. DIC can develop with severe abruption. If fibrinogen is <150 mg %, estimated blood loss equals 2000 ml, and if fibrinogen is <100 mg %, consider FFP to prevent further bleeding.
• Type and antibody screen is important to identify Rh-negative patients who may need Rh immune globulin.
Ultrasound should include fetal presentation and status, amniotic fluid volume, placental location, as well as any evidence of hematoma (retroplacental, subchorionic, or preplacental).
Treatment is dependent on gestational age of the fetus, severity of the abruption, and maternal status. Stabilization of the mother is the first priority.
ACUTE GENERAL Rx
• Initial assessment for signs of maternal hemodynamic compromise or hemorrhagic shock; large-bore intravenous access, with crystalloid fluid resuscitation using a replacement of 3 ml LR solution for every 1 ml estimated blood loss.
• Indwelling Foley catheter to monitor urine output and maternal volume status, with a goal of 30 ml/hr urine output.
• Assess fetal status and gestational age, using sonogram and continuous fetal heart rate monitoring.
• Because of the unpredictable nature of abruptions, cross-matched blood should be made available during the initial resuscitation period.
• In the term fetus or where lung maturity has been documented, delivery is indicated.
• In the preterm fetus or with an immature lung profile, consideration should be given for betamethasone 12.5 mg IM q24h for two doses and then delivery, depending on the severity of the abruption and the likelihood of fetal complications from preterm birth.
• C-section should be reserved for cases of fetal distress or for standard obstetric indications.
• In select cases, such as severe prematurity with a stable mother and mild contractions, magnesium sulfate can be used for tocolysis, 6 g IV loading dose then 3 g/hr maintenance, to allow for course of steroids.