, Question 1
A pregnant patient with a history of type 1 diabetes and a BMI of 34 is at 10
weeks gestation. Which laboratory finding best reflects the maternal
physiological adaptation that most directly increases fetal risk for neural tube
defects?
A. Elevated hemoglobin A1c
B. Elevated serum creatinine
C. Low serum ferritin
D. Elevated thyroid-stimulating hormone
Correct Answer: A - Elevated hemoglobin A1c
RATIONALE
Elevated HbA1c reflects poor periconceptional glycemic control,
which is strongly associated with neural tube defects via
hyperglycemia-induced oxidative stress and apoptosis in the
developing neural tube. Serum creatinine and TSH do not directly
predict NTD risk; low ferritin causes anemia but is not a primary
teratogenic mechanism.
Question 2
Which statement accurately describes the direction and oxygenation of blood
flow in fetal circulation?
A. The ductus arteriosus shunts oxygenated blood from the pulmonary
artery to the aorta.
B. The foramen ovale allows oxygenated blood to bypass the pulmonary
circulation by moving from the right atrium to the left atrium.
C. The ductus venosus carries deoxygenated blood from the umbilical
arteries to the inferior vena cava.
D. The umbilical vein carries deoxygenated blood from the fetus to the
placenta.
Correct Answer: B - The foramen ovale allows oxygenated blood
Page 2
, to bypass the pulmonary circulation by moving from the right
atrium to the left atrium.
RATIONALE
The foramen ovale shunts oxygenated blood from the right atrium to
the left atrium, bypassing the nonfunctional fetal lungs. The ductus
arteriosus shunts deoxygenated blood from the pulmonary artery to the
descending aorta; the ductus venosus carries oxygenated blood from
the umbilical vein to the IVC; the umbilical vein carries oxygenated
blood to the fetus, while umbilical arteries carry deoxygenated blood
away.
Question 3
A patient at 18 weeks gestation reports a sudden onset of sharp, unilateral
pelvic pain and light vaginal spotting after intercourse. Which physiological
change of pregnancy most likely explains this presentation?
A. Increased progesterone causing smooth muscle relaxation and venous
stasis
B. Mechanical compression of the inferior vena cava by the gravid uterus
C. Engorgement and increased vascularity of the cervix
D. Physiologic anemia of pregnancy due to plasma volume expansion
Correct Answer: C - Engorgement and increased vascularity of
the cervix
RATIONALE
Cervical ectropion and increased vascularity during pregnancy can
cause postcoital spotting and pelvic discomfort. Progesterone-induced
smooth muscle relaxation can cause round ligament pain but not
typically spotting; vena cava compression causes supine hypotension;
physiologic anemia is unrelated to these symptoms.
Page 3
A pregnant patient with a history of type 1 diabetes and a BMI of 34 is at 10
weeks gestation. Which laboratory finding best reflects the maternal
physiological adaptation that most directly increases fetal risk for neural tube
defects?
A. Elevated hemoglobin A1c
B. Elevated serum creatinine
C. Low serum ferritin
D. Elevated thyroid-stimulating hormone
Correct Answer: A - Elevated hemoglobin A1c
RATIONALE
Elevated HbA1c reflects poor periconceptional glycemic control,
which is strongly associated with neural tube defects via
hyperglycemia-induced oxidative stress and apoptosis in the
developing neural tube. Serum creatinine and TSH do not directly
predict NTD risk; low ferritin causes anemia but is not a primary
teratogenic mechanism.
Question 2
Which statement accurately describes the direction and oxygenation of blood
flow in fetal circulation?
A. The ductus arteriosus shunts oxygenated blood from the pulmonary
artery to the aorta.
B. The foramen ovale allows oxygenated blood to bypass the pulmonary
circulation by moving from the right atrium to the left atrium.
C. The ductus venosus carries deoxygenated blood from the umbilical
arteries to the inferior vena cava.
D. The umbilical vein carries deoxygenated blood from the fetus to the
placenta.
Correct Answer: B - The foramen ovale allows oxygenated blood
Page 2
, to bypass the pulmonary circulation by moving from the right
atrium to the left atrium.
RATIONALE
The foramen ovale shunts oxygenated blood from the right atrium to
the left atrium, bypassing the nonfunctional fetal lungs. The ductus
arteriosus shunts deoxygenated blood from the pulmonary artery to the
descending aorta; the ductus venosus carries oxygenated blood from
the umbilical vein to the IVC; the umbilical vein carries oxygenated
blood to the fetus, while umbilical arteries carry deoxygenated blood
away.
Question 3
A patient at 18 weeks gestation reports a sudden onset of sharp, unilateral
pelvic pain and light vaginal spotting after intercourse. Which physiological
change of pregnancy most likely explains this presentation?
A. Increased progesterone causing smooth muscle relaxation and venous
stasis
B. Mechanical compression of the inferior vena cava by the gravid uterus
C. Engorgement and increased vascularity of the cervix
D. Physiologic anemia of pregnancy due to plasma volume expansion
Correct Answer: C - Engorgement and increased vascularity of
the cervix
RATIONALE
Cervical ectropion and increased vascularity during pregnancy can
cause postcoital spotting and pelvic discomfort. Progesterone-induced
smooth muscle relaxation can cause round ligament pain but not
typically spotting; vena cava compression causes supine hypotension;
physiologic anemia is unrelated to these symptoms.
Page 3
