How does Tidal volume increase in pregnancy?

[anbuitachi]

So tidal volume increases during pregnancy, but does anyone know how this occurs. Cause the way I think about it, pregnancy pushes upwards which should decrease lung capacity... and thus reduce tidal volume..

Thanks

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[jdh71]

So tidal volume increases during pregnancy, but does anyone know how this occurs. Cause the way I think about it, pregnancy pushes upwards which should decrease lung capacity... and thus reduce tidal volume..

Thanks

Tidal volumes are just your normal breathing volumes. Pregnant women take bigger breaths because they need the increase in minute ventilation, and they can't make it all up in with respiratory rate alone. Blame God or evolution (or maybe the aliens). But either way, it's a natural (likely hormonal driven) compensation, the transverse diameter of the chest increases resulting from a widened subcostal angle which basically opposes the increase in abdominal volume.

TLC and RV do go down a bit with pregnancy, but FVC goes up and FEV1 stays about the same. Take together there are some changes but it all evens out.

Neat.

 

[anbuitachi]

Thanksss!!