Pregnancy, Fetal and Neonatal Physiology MCQs

Physiology · 57 free questions with answers & explanations.

1. A 32-week preterm neonate is intubated for respiratory distress syndrome (RDS). The primary physiological deficiency causing RDS is:
2. Fetal hemoglobin (HbF) has a higher oxygen affinity than adult HbA. The physiological basis for this difference and its functional significance in the fetus is:
3. At birth, the transition from fetal to neonatal circulation requires closure of several shunts. The mechanism driving functional closure of the foramen ovale immediately after birth is:
4. During pregnancy, the maternal glomerular filtration rate (GFR) increases by 40–50%. The primary mechanism responsible for this gestational hyperfiltration is:
5. A pregnant woman at 28 weeks gestation presents with physiological anemia. Her Hb is 10.2 g/dL, hematocrit 31%. The physiological mechanism responsible is:
6. The fetal haemoglobin (HbF) oxygen dissociation curve is shifted to the LEFT compared to adult HbF. The primary reason is:
7. Immediately at birth, which haemodynamic change results PRIMARILY from the baby's first breath?
8. Maternal GFR increases by approximately 40–50% during pregnancy. The primary mechanism is:
9. Neonatal surfactant deficiency (respiratory distress syndrome) results in reduced lung compliance because:
10. Fetal hemoglobin (HbF) has higher oxygen affinity than adult hemoglobin (HbA). The molecular basis of this difference is:
11. In the fetal circulation, the ductus arteriosus directs blood from the pulmonary artery to the aorta. At birth, the ductus arteriosus closes functionally within hours. The primary physiological trigger for this closure is:
12. During normal pregnancy at 28-32 weeks, cardiac output increases by approximately 40-50% above pre-pregnancy values. The primary hemodynamic driver of this increase (in order of contribution) is:
13. A premature neonate at 28 weeks gestation develops respiratory distress syndrome (RDS). The pathophysiological basis relates directly to the ontogeny of surfactant production. Type II pneumocytes begin producing surfactant in clinically significant amounts beginning at:
14. A 28-week pregnant woman has ABG: pH 7.44, PaCO2 30 mmHg, HCO3 20 mEq/L. How should this be interpreted in the context of normal pregnancy physiology?
15. Fetal hemoglobin (HbF) has higher oxygen affinity than adult HbF (HbA). Which molecular property of HbF accounts for its LEFT-shifted oxygen dissociation curve?
16. At birth, the first breath of a neonate triggers closure of the foramen ovale. Which sequence of hemodynamic events is the CORRECT mechanism?
17. A term neonate develops jaundice on day 2 of life with indirect bilirubin 14 mg/dL. Which physiological mechanism is PRIMARILY responsible for physiological jaundice of the newborn?
18. Placental function undergoes marked physiological changes in the third trimester. Which statement about uteroplacental blood flow BEST describes why placental insufficiency causes symmetric IUGR when it occurs early vs. asymmetric IUGR when it occurs late?
19. A 28-week-pregnant woman has her cardiac output measured. Compared to her pre-pregnancy baseline, which combination of changes is MOST accurate?
20. Fetal hemoglobin (HbF) has a higher oxygen affinity than adult hemoglobin (HbA). What is the physiological basis of this difference and why is it critical for fetal oxygen acquisition?
21. At birth, the ductus arteriosus begins to close within hours. Which of the following is the MOST important trigger for functional closure of the ductus arteriosus?
22. In the immediate neonatal period, which of the following physiological transitions is responsible for converting the fetal circulatory pattern (with right-to-left shunt at the foramen ovale) to an adult pattern?
23. Which of the following cardiovascular changes of normal pregnancy is CORRECTLY matched with its physiological basis?
24. Fetal hemoglobin (HbF, α2γ2) has a left-shifted oxygen dissociation curve compared to adult HbA. At the placenta, the Bohr effect facilitates O2 transfer from mother to fetus via which mechanism?
25. In the fetal circulation, the ductus venosus shunts blood from the umbilical vein directly to the inferior vena cava. Which valve-like structure regulates this shunt, and through which foramen does oxygenated blood preferentially pass to reach the left heart?
26. A neonate born at 36 weeks gestation develops progressive respiratory distress within 2 hours of birth with grunting, nasal flaring, and reticular-granular pattern on CXR. Which surfactant phospholipid component, most critical for alveolar stability, is deficient?
27. A newborn's PaO2 rises from 25 mmHg (fetal) to 95 mmHg after birth. This rise in PaO2 causes closure of the ductus arteriosus primarily by which mechanism?
28. At 32 weeks gestation, fetal haemoglobin (HbF) has a P50 of 19 mmHg compared to adult HbF P50 of 27 mmHg. This left-shifted oxygen dissociation curve of HbF serves which physiological function in the placenta?
29. At birth, when the neonate takes its first breath, the series of cardiovascular changes that convert fetal to neonatal circulation occur rapidly. Which sequence correctly describes the closure of fetal cardiovascular shunts?
30. During the last trimester, maternal plasma volume expands by approximately 40–50% while red cell mass increases only 20–30%, resulting in the physiological anaemia of pregnancy. What is the primary stimulus for this disproportionate plasma expansion?
31. Surfactant (dipalmitoylphosphatidylcholine, DPPC) is produced by type II alveolar cells beginning at approximately 24 weeks gestation and reaches functional levels by about 35 weeks. By what physical mechanism does surfactant prevent alveolar collapse (atelectasis) at end-expiration?
32. Fetal haemoglobin (HbF) has a higher oxygen affinity than adult HbA. The primary reason for this difference is:
33. At birth, the first breath triggers lung expansion. Which of the following cardiovascular changes occurs primarily as a result of the rise in pulmonary blood flow and the fall in pulmonary vascular resistance?
34. During normal pregnancy, maternal plasma volume expands by approximately what percentage by the third trimester, and which hormone is primarily responsible?
35. A newborn delivered at 30 weeks gestation develops progressive respiratory distress within 4 hours of birth. Chest radiograph shows a 'ground-glass' pattern. The primary pathophysiological defect is:
36. During pregnancy, the maternal kidney increases creatinine clearance. Which mechanism is primarily responsible for the rise in GFR during pregnancy?
37. During normal pregnancy, cardiac output increases by approximately 40–50%. Which of the following contributes MOST to this increase?
38. Fetal haemoglobin (HbF, α2γ2) has a higher oxygen affinity than adult HbA. This is because:
39. At birth, the newborn's lungs must expand and fill with air for the first time. The critical surfactant that lowers surface tension and prevents alveolar collapse (atelectasis) is predominantly synthesized from:
40. At birth, the ductus arteriosus normally closes within 10–15 hours. The primary stimulus for its functional closure in term neonates is:
41. A 30-week preterm neonate develops respiratory distress and chest X-ray shows a 'ground glass' appearance with air bronchograms. Surfactant therapy is administered. Which lab measurement of amniotic fluid predicts fetal lung maturity most reliably?
42. A woman at 32 weeks gestation has a GFR of 165 mL/min (versus her pre-pregnancy value of 110 mL/min). The serum creatinine is 0.5 mg/dL. Why is GFR elevated in pregnancy, and what is the clinical significance?
43. The fetal hemoglobin (HbF) oxygen dissociation curve is shifted to the LEFT compared to adult HbA. What is the primary physiological mechanism of this leftward shift, and why is it important?
44. At birth, what triggers the initial breath in a neonate?
45. Maternal hyperventilation during pregnancy results in a state of mild respiratory alkalosis. What is the correct arterial blood gas pattern expected in the third trimester?
46. Fetal circulation includes which of the following unique shunts that DIRECTLY bypasses the pulmonary circulation?
47. At term, a woman's cardiac output is approximately 40–50% higher than her pre-pregnancy baseline. Which change makes the greatest single contribution to this increase?
48. Fetal haemoglobin (HbF) has a higher oxygen affinity than adult HbA. At physiological pH, the P50 of HbF is approximately 18–20 mmHg versus 26–27 mmHg for HbA. Which molecular feature primarily accounts for this difference?
49. Immediately after birth, the neonatal ductus arteriosus begins to close. Which is the most important physiological stimulus triggering functional closure within the first hours of life?
50. A pregnant woman at 32 weeks complains of positional dizziness and near-syncope when lying supine. Her blood pressure drops from 120/80 to 90/60 mmHg in the supine position. What is the underlying mechanism?
51. Human chorionic gonadotropin (hCG) prevents luteolysis in early pregnancy. Beyond 10–12 weeks, the corpus luteum involutes despite persistently high hCG levels. What physiological event explains this 'luteo-placental shift'?
52. In pregnancy, the normal physiological changes in respiratory function include:
53. Fetal haemoglobin (HbF) has a higher oxygen affinity than adult HbF (HbA). The physiological reason for this is:
54. The first breath of a newborn requires a very high inspiratory pressure (~50–70 cmH2O) to expand the lungs. The primary cause of this high resistance is:
55. In the fetal circulation, which structure allows oxygenated blood from the umbilical vein to bypass the hepatic sinusoids and enter the inferior vena cava directly?
56. Cardiac output in pregnancy increases by approximately 40–50% by the end of the first trimester. The primary mechanism driving this early increase is:
57. A neonate born at 34 weeks is found to have a patent ductus arteriosus (PDA). Physiologically, the ductus arteriosus normally closes soon after birth primarily because of: