Topic: Pregnancy menstrual cycle, lactation
Question: Enumerate the cardiovascular and respiratory physiological changes associated with pregnancy.
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key cardiovascular and respiratory physiological changes that occur during pregnancy:
Cardiovascular changes:
– Increased blood volume by 30-50% to supply the fetus. Plasma volume increases more than red cell volume leading to physiological anemia.
– Increased cardiac output by 30-50%. Heart rate increases. Stroke volume and heart size increase.
– Decreased systemic vascular resistance due to vasodilation. Leads to lower blood pressure.
– Slight increase in coagulability of blood. Risk of venous thromboembolism goes up.
Respiratory changes:
– Increased minute ventilation and oxygen consumption by 20-50%.
– Mild compensated respiratory alkalosis from hyperventilation. Lowers PaCO2 and raises pH.
– Elevated diaphragm level by up to 4cm due to enlargement of uterus. Decreased functional residual capacity.
– Increased blood flow to breasts and mucus production increases risk of pulmonary aspiration.
In summary, major cardiovascular adaptations include increased blood volume, cardiac output, and heart size along with lowered vascular resistance and blood pressure. Major respiratory changes include hyperventilation, respiratory alkalosis, and altered lung volumes and capacities. These changes support increased metabolic demands during pregnancy. (
