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How does pregnancy change the position of the heart and diaphragm?
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prenatal development
An ultrasound image of a human fetus.
During pregnancy, the enlarging uterus exerts upward pressure, which elevates the diaphragm.1
This displacement of the diaphragm subsequently pushes the heart upward, to the left, and slightly forward, positioning it closer to the chest wall beneath the breast. As gestation nears its end, the heart may be raised until it lies at nearly a right angle to the long axis of the body, a change that often involves some rotation of the organ. While these positional shifts can sometimes lead a physician to mistakenly suspect cardiac enlargement, a healthy heart typically does not enlarge significantly during pregnancy.1