If you’re preparing for the United States Medical Licensing Examination® (USMLE®) Step 1 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.
Fifty pregnant women participate in a study during which various hormone levels are measured at different gestational times. Which of the following hormone profiles shown in the graph will most likely be seen in a woman with a normal pregnancy?
- CRH = corticotropin-releasing hormone
- hCG = human chorionic gonadotropin
- hPL = human placental lactogen
A. W: hCG, X: hPL, Y: CRH
B. W: progesterone, X: CRH, Y: hCG
C. W: 17-OH progesterone, X: hCG, Y: progesterone
D. W: hPL, X: hCG, Y: 17-OH progesterone
E.W: hCG, X: 17-OH progesterone, Y: progesterone
The correct answer is A.
Kaplan Medical explains why
hCG rises early during gestation, peaks around week 10, and then declines (curve W). hPL rises slowly during gestation in proportion to fetal mass (curve X). CRH levels rise sharply late in pregnancy (curve Y).
Why the other answers are wrong
Choice B: Progesterone levels rise gradually during gestation, CRH appears in the third trimester, whereas hCG rises early, peaks around week 10, and then declines.
