Joints—The hormones made during pregnancy cause the ligaments that support your joints to become relaxed. This makes the joints more mobile and at risk of injury. Avoid jerky, bouncy, or high-impact motions that can increase your risk of being hurt.
Balance—The extra weight in the front of your body shifts your center of gravity. This places stress on joints and muscles, especially those in your pelvis and lower back. Because you are less stable and more likely to lose your balance, you are at greater risk of falling.
Breathing—When you exercise, oxygen and blood flow are directed to your muscles and away from other areas of your body. While you are pregnant, your need for oxygen increases. This may affect your ability to do strenuous exercise, especially if you are overweight or obese.