A 36-year-old woman, gravida 2 para 1, at 35 weeks gestation comes to the labor and delivery unit due to vaginal bleeding and constant back pain for the past hour. The patient has a history of chronic hypertension that has been well controlled with labetalol throughout the pregnancy. Prenatal laboratory tests and ultrasounds have been normal. She does not use tobacco, alcohol, or illicit drugs. Temperature is 37.1 C (98.8 F), blood pressure is 104/70 mm Hg, and pulse is 118/min. Physical examination shows a smooth, firm, and distended uterus with a fundal height of 38 cm. Speculum examination reveals a small amount of bleeding and a closed cervix. The first 10 minutes of fetal monitoring show a baseline heart rate of 160/min, minimal variability, and 3 late decelerations. Uterine contractions are observed every 1-2 minutes. Which of the following is the most likely diagnosis in this patient?

Question

A 36-year-old woman, gravida 2 para 1, at 35 weeks gestation comes to the labor and delivery unit due to vaginal bleeding and constant back pain for the past hour.  The patient has a history of chronic hypertension that has been well controlled with labetalol throughout the pregnancy.  Prenatal laboratory tests and ultrasounds have been normal.  She does not use tobacco, alcohol, or illicit drugs.  Temperature is 37.1 C (98.8 F), blood pressure is 104/70 mm Hg, and pulse is 118/min.  Physical examination shows a smooth, firm, and distended uterus with a fundal height of 38 cm.  Speculum examination reveals a small amount of bleeding and a closed cervix.  The first 10 minutes of fetal monitoring show a baseline heart rate of 160/min, minimal variability, and 3 late decelerations.  Uterine contractions are observed every 1-2 minutes.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_da12_1e73_bc81_f56d2787a11c_MD0003_00 This patient with vaginal bleeding; a firm, distended uterus; and fetal decelerations has abruptio placentae. Placental abruption occurs when maternal vessels rupture at the uteroplacental interface, causing premature separation of the placenta from the uterus. A common risk factor is chronic hypertension. Maternal hypertension, regardless of well-controlled blood pressure, is associated with widespread endothelial dysfunction. This dysfunction impairs normal development of the spiral arteries that supply blood to the fetus and placenta; the result is abnormally high-resistance spiral arteries that lead to low placental perfusion, ischemia, and possible infarction, all of which increase the risk of abruptio placentae. In addition, chronic endothelial dysfunction increases vessel frailty and the risk of vessel rupture at the uteroplacental interface. Other risk factors for abruptio placentae include tobacco or cocaine use (due to placental ischemia) and abdominal trauma. Although most patients with abruptio placentae have heavy vaginal bleeding, up to 20% have minimal or no bleeding because blood is concealed within the intrauterine cavity. These patients typically have focal pain (eg, back pain, suggesting posterior placental rupture), an abnormally distended uterus (eg, measuring 38 cm at 35 weeks gestation), and high-frequency contractions due to increasing intrauterine pressure and volume. As more of the placenta detaches, fetal hypoxia can occur, as evidenced by abnormalities on the fetal heart rate tracing (eg, late decelerations). (Choice B) Intraamniotic infection can cause abdominal pain; however, patients are typically febrile with fundal tenderness. (Choice C) Placenta previa, placental implantation over the cervix, causes painless vaginal bleeding. Placenta previa (Choice D) Preterm labor is contractions that cause cervical dilation at <37 weeks gestation. Labor pain is typically intermittent because the uterus relaxes between contractions. In contrast, this patient has constant pain and a closed cervix. (Choice E) Uterine rupture commonly causes abdominal pain, vaginal bleeding, and fetal heart rate abnormalities. However, patients typically have diminishing contractions and fetal parts palpable through the maternal abdominal wall. Uterine rupture (Choice F) Vasa previa can present with vaginal bleeding due to injury to fetal vessels overlying the cervix; however, the bleeding is typically painless. Vasa previa Educational objective: Abruptio placentae, premature placental detachment from the uterus prior to fetal delivery, is caused by maternal vessel rupture at the uteroplacental interface. Patients typically have acute pain, vaginal bleeding, and abnormalities on fetal heart rate tracing. Chronic hypertension, regardless of blood pressure control, is a risk factor due to underlying maternal endothelial dysfunction. References: Placental abruption: epidemiology, risk factors and consequences. (http://www.ncbi.nlm.nih.gov/pubmed/21241259) Is the perinatal outcome of placental abruption modified by clinical presentation? (http://www.ncbi.nlm.nih.gov/pubmed/21490793)

A 36-Year-Old Woman, Gravida 2 Para 1, at 35 Weeks