Which of the following decreases during pregnancy?: (A) Systemic venous resistance, (B) CO, (C) HR, (D) Plasma volume
Answer is A. Ans. A. Systemic venous resistanceChanges during pregnancy:* Increased in cardiac output* Increase in HR* Increase in plasma volume* Decrease in SVR by (-21%) due to smooth muscle relaxing effect of progesterone, NO, prostaglandins or ANP.* In spite of the large increase in cardiac output, the maternal BP (BP=COxSVR) is decreased due to decrease in SVR. There is overall decrease in diastolic blood pressure (BP) and mean arterial pressure (MAP) by 5-10mmHg