Blood! Cardiovascular system refers to the heart pumping blood around the body.
With this question firstly you can think beyond football players. Technology can be used to better understand everyone's health, including people and animals. Think about things like injuries that cant be seen, such as concussions. If a football player wanted to better understand their health they could get an MRI or use other forms of technology. Outside of injuries there is also the health aspect, you can check your cholesterol and blood rate and all that very easily now a days, making it quite easy to check if you are healthy.
A pregnant woman should be immediately seen for any obvious health issues. So the answer is yes: if a pregnant woman struggles with breathing and/or has an iron deficiency she should check in with her doctor.
