<prompt> Which of the following decreases during pregnancy?Systemic venous resistanceCOHRPlasma volume  <response>: 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 BPCOxSVR is decreased due to decrease in SVR. There is overall decrease in diastolic blood pressure BP and mean arterial pressure MAP by 5-10mmHg 