Your expanded respiratory and circulatory systems are seeing to it that the baby is getting plenty of oxygen. Your body is now carrying more blood and more oxygen-rich hemoglobin. These increases cause the oxygen level in your blood to increase, ensuring an adequate supply to your growing baby. Improving your posture will help you to breathe better, both during pregnancy and afterward. Practice sitting and standing with your back straight and your shoulders back, relaxed, and down.
Aerobic exercise is also beneficial throughout pregnancy.
It will improve your breathing and lower your pulse rate. Take care, however, not to overexert yourself. Consult your doctor about a safe exercise program for late pregnancy. When sleeping, lying propped up on pillows or on your side may help lessen the pressure on your diaphragm. If none of these measures seem to help enough, hang in there.