A pregnant woman has low blood pressure despite having tachycardia. Which physiological change of pregnancy is the most likely cause?

1. A

   Decreased cardiac output

2. B

   Increased systemic vascular resistance

3. C

   Decreased systemic vascular resistance

4. D

   Increased blood viscosity

Appeared in: NORCET-11 Prelims

Explanation

• Systemic vascular resistance decreases in pregnancy due to vasodilation from hormones like progesterone and relaxin.
• This vasodilation lowers blood pressure even as heart rate and cardiac output increase.
• Decreased SVR is the main physiological reason for low BP with tachycardia in pregnancy.

Why Other Options Were Wrong

• Option A: Cardiac output increases during pregnancy, not decreases. Decreased cardiac output would cause hypotension in heart failure, not in normal pregnancy.
• Option B: Systemic vascular resistance actually decreases in pregnancy. Increased SVR would cause hypertension, not hypotension.
• Option D: Blood viscosity increases slightly due to higher red cell mass, but this does not cause hypotension.

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to Physiological cardiovascular adaptations in pregnancy affecting blood pressure to guide bedside assessment, documentation, and the next nursing action.
• Nurses should expect lower blood pressure and higher heart rate in healthy pregnant women, especially in the second trimester.
• Recognizing normal physiological hypotension prevents unnecessary interventions for mild low BP in pregnancy.
• What if? If a pregnant woman had increased SVR (e.g., preeclampsia), she would develop hypertension, not hypotension.

How to Approach the Question

• Identify the clinical scenario: pregnant woman, low BP, tachycardia.
• Recall normal cardiovascular adaptations in pregnancy.
• Eliminate options that contradict known physiological changes (e.g., decreased cardiac output, increased SVR).
• Select the option that matches the mechanism for hypotension in pregnancy.
• Use process of elimination for distractors based on their effects on BP.

Concept Tested & Keywords

• Concept Tested: Physiological cardiovascular adaptations in pregnancy affecting blood pressure
• Stem keywords: pregnant woman, low blood pressure, tachycardia, physiological change
• Lead-in keywords: most likely cause
• Clinical cues: Pregnancy
• Clinical cues: Low BP with tachycardia

Question ID

Q0WR28cHTuv49tOR4fCEk7

Copy ID

Reference Book

E6 Physiology Guyton 4SAE Part 3 p. 61-63

E6 Obstetrics Williams p. 48-69