If you’re preparing for the United States Medical Licensing Examination® (USMLE®) Step 3 exam, you might want to know which questions are most often missed by test-prep takers. Check out this example from Kaplan Medical, and read an expert explanation of the answer. Also check out all posts in this series.
The AMA and Kaplan have teamed up to support you in reaching your goal of passing the USMLE® or COMLEX-USA®. If you're looking for additional resources, Kaplan provides free access to tools for pre-clinical studies, including Kaplan’s Lecture Notes series, Integrated Vignettes, Shelf Prep and more.
This month’s stumper
A 26-year-old G1P0 woman who is 8-weeks pregnant presents with vaginal bleeding for the past three days. She denies any passage of blood clots and has no abdominal or pelvic pain. Vital signs and physical examination are normal. Transvaginal ultrasound demonstrates a gestational sac containing a fetal pole and a yolk sac. The fetal heart motion is detected, and crown rump length measurements are consistent with an 8-week gestation. There is a small crescent-shaped hypoechoic area next to the gestational sac.
What is the next step in management of this patient?
A. Bedrest for the remainder of the pregnancy.
B. Serum beta-HCG.
C. Reassurance to the patient that the ultrasound was normal.
D. Suction curettage.
E. Follow-up ultrasound in 1-week.
The correct answer is E.
Kaplan Medical explains why
The ultrasound demonstrates a viable intrauterine pregnancy that corresponds to the patient’s last menstrual period. The crescent-shaped hypoechoic area adjacent to the gestational sac is indicative of subchorionic hemorrhage. This is bleeding that occurs between the endometrium and the gestational sac.
The greater the size of the subchorionic hemorrhage, the greater the risk of spontaneous abortion. Small hemorrhages, as in this case, often spontaneously resolve on their own. The best management for small subchorionic hematomas is to follow the patient's symptoms and repeat the ultrasound to evaluate for interval resolution or change.
Why the other answers are wrong
Choice A: Bedrest for the remainder of the pregnancy is not indicated for a small subchorionic hemorrhage. Bedrest is often recommended in the setting of preeclampsia, not at issue here.
Choice B: A serum beta-HCG will not provide any additional information about the pregnancy. The ultrasound confirms a viable intrauterine pregnancy that corresponds to the patient's last menstrual period. The beta-HCG value may provide information if the ultrasound findings do not match the expected findings of an 8-week gestation.
Choice C: Reassurance that the ultrasound was normal is inaccurate and misleading. Small subchorionic hemorrhages often do spontaneously resolve. However, these hematomas can enlarge and lead to a spontaneous abortion. Therefore, the patient should be followed by repeating the ultrasound in a short interval to assess for resolution or change.
Choice D: Suction curettage is inappropriate. The ultrasound documented a viable intrauterine pregnancy. A small subchorionic hemorrhage does not indicate nonviability. Suction curettage can be performed following a spontaneous abortion or after the detection of embryonic demise. This procedure is performed to remove any retained products of conception to prevent bleeding and infection.
For more prep questions on USMLE Steps 1, 2 and 3, view other posts in this series.