Which of the following statements about exercising during pregnancy is true?

There must be no exercise at high altitudes. The higher the altitude gets, it will increase the pressure. So when a pregnant women is having an exercise, like jogging in a mountain, it is too risky for her to be in danger and to her child. This can be a factor of her stress and too much force she exerted can damage her condition or worse it can lead to miscarriage.

Can you explain it well?