What happens to tidal volume during pregnancy?

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Multiple Choice

What happens to tidal volume during pregnancy?

During pregnancy the respiratory system adapts to meet higher oxygen needs and fetal gas exchange. Progesterone increases the respiratory drive, making ventilation more responsive to CO2, so breaths become deeper. This leads to a rise in tidal volume—typically about 30–40% larger than pre-pregnancy. Because of the larger breaths, minute ventilation increases even if the breathing rate doesn’t change much. The diaphragm is pushed upward by the growing uterus, which lowers some lung volumes, but overall tidal volume rises to support increased metabolic demand. So the best answer is that tidal volume increases. The other options don’t fit the physiological changes of pregnancy.

During pregnancy the respiratory system adapts to meet higher oxygen needs and fetal gas exchange. Progesterone increases the respiratory drive, making ventilation more responsive to CO2, so breaths become deeper. This leads to a rise in tidal volume—typically about 30–40% larger than pre-pregnancy. Because of the larger breaths, minute ventilation increases even if the breathing rate doesn’t change much. The diaphragm is pushed upward by the growing uterus, which lowers some lung volumes, but overall tidal volume rises to support increased metabolic demand. So the best answer is that tidal volume increases. The other options don’t fit the physiological changes of pregnancy.

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