Final answer:
A normal cardiovascular change during the second trimester of pregnancy is an increased heart rate, which occurs alongside a significant increase in blood volume by approximately 30 percent to meet the needs of the fetus.
Step-by-step explanation:
The nurse is describing cardiovascular system changes that occur during pregnancy, and a normal finding for a client in the second trimester would be A) Increased heart rate. During pregnancy, the circulatory system undergoes significant changes, including a substantial increase in blood volume which, by the time of childbirth, exceeds the preconception volume by approximately 30 percent or 1-2 liters. This increased blood volume is essential to meet the demands of fetal nourishment and waste removal. Moreover, the increased blood volume is accompanied by a moderate rise in both the pulse and blood pressure. These changes are normal adaptations that facilitate the physiological requirements during pregnancy. Heart murmurs can occur, but they are not a uniform change in pregnancy, and elevated blood pressure is a concern rather than a norm.