A 20-year-old woman comes to the emergency department due to vaginal bleeding and lower abdominal pain that began 3 days ago. The patient describes the bleeding as heavier than a period; she passed some vaginal clots a few hours ago. Menarche was at age 13, and she has often gone months without a menstrual period. The patient's last menstrual period was approximately 7 weeks ago. She is sexually active and uses condoms for contraception. Temperature is 37.2 C (99 F), blood pressure is 120/74 mm Hg, and pulse is 80/min. Abdominal examination shows mild lower abdominal tenderness but no rebound or guarding. On speculum examination, there is no active vaginal bleeding, and the cervical os is closed. Laboratory results are as follows: A transvaginal ultrasound does not visualize an intrauterine pregnancy, free fluid, or adnexal masses. Which of the following is the best next step in management of this patient?

Question

A 20-year-old woman comes to the emergency department due to vaginal bleeding and lower abdominal pain that began 3 days ago.  The patient describes the bleeding as heavier than a period; she passed some vaginal clots a few hours ago.  Menarche was at age 13, and she has often gone months without a menstrual period.  The patient's last menstrual period was approximately 7 weeks ago.  She is sexually active and uses condoms for contraception.  Temperature is 37.2 C (99 F), blood pressure is 120/74 mm Hg, and pulse is 80/min.  Abdominal examination shows mild lower abdominal tenderness but no rebound or guarding.  On speculum examination, there is no active vaginal bleeding, and the cervical os is closed.  Laboratory results are as follows:  A transvaginal ultrasound does not visualize an intrauterine pregnancy, free fluid, or adnexal masses.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_da28_8cc9_bc81_59f5f80baebb_MD0003_00 This patient with vaginal bleeding and positive β-hCG has first-trimester bleeding, which requires evaluation with transvaginal ultrasonography (TVUS) and serum β-hCG measurements to determine pregnancy location. This patient's ultrasound is nondiagnostic (eg, no intrauterine pregnancy, free fluid, or adnexal masses), which is expected because her quantitative β-hCG level (ie, 1,000 mIU/mL) is below the threshold at which an intrauterine pregnancy can be visualized by TVUS (ie, below the discriminatory zone [β-hCG <3,500 mIU/mL]). Therefore, she has a pregnancy of unknown location. The most common cause of a pregnancy of unknown location is early gestation of a normal intrauterine pregnancy; however, other potential etiologies are a completed spontaneous abortion, nonviable intrauterine pregnancy (missed abortion), and ectopic pregnancy, all of which require further evaluation for definitive diagnosis (Choice D). Because each type of pregnancy follows a characteristic β-hCG pattern, quantitative β-hCG levels are repeated every 48 hours: Early but viable intrauterine pregnancies typically have a ≥35%-50% rise in β-hCG every 48 hours. Completed spontaneous abortions cause β-hCG levels to decrease precipitously because the pregnancy has been evacuated. Ectopic and nonviable intrauterine pregnancies (eg, anembryonic gestations) usually cause <35% rise in β-hCG due to abnormal pregnancy development. Patients typically require serial quantitative β-hCG measurements until the level reaches the discriminatory zone, at which point a repeat transvaginal ultrasound is performed (Choice F). Those with an abnormally rising β-hCG level require close follow-up due to the risk of ectopic pregnancy. (Choice A) Anti-D immunoglobulin is administered to Rh(D)-negative patients after pregnancy-related bleeding (eg, spontaneous abortion, ectopic pregnancy) due to the risk of Rh(D) alloimmunization and hemolytic disease of the newborn in future pregnancies. This patient is Rh(D) positive. Rh(D) alloimmunization (Choices B and C) Methotrexate and diagnostic laparoscopy are treatment options for ectopic pregnancy, which has not been definitively diagnosed in this patient. Methotrexate is typically used in patients with an unruptured ectopic pregnancy. Diagnostic laparoscopy is performed in patients with hemodynamic instability (ie, ruptured ectopic pregnancy) or patients with contraindications to methotrexate (eg, immunodeficiency, breastfeeding). Educational objective: Patients with vaginal bleeding and positive β-hCG require transvaginal ultrasonography to determine pregnancy location. Patients with a nondiagnostic ultrasound result (eg, no intrauterine pregnancy, free fluid, or adnexal masses) require a repeat quantitative β-hCG level in 48 hours to evaluate for potential ectopic pregnancy. References: ACOG practice bulletin No. 94: medical management of ectopic pregnancy. (http://www.ncbi.nlm.nih.gov/pubmed/18515537) Early pregnancy bleeding. (http://www.ncbi.nlm.nih.gov/pubmed/27166462)

A 20-Year-Old Woman Comes to the Emergency Department Due to Vaginal