. Author manuscript; available in PMC: 2023 Jul 24.

Published in final edited form as: J Clin Pharmacol. 2023 Jun;63(Suppl 1):S34–S50. doi: 10.1002/jcph.2227

Table 4.

Respiratory-Associated Changes During Pregnancy

Covariate	Pregnancy-Associated Changes
Vital capacity	No change
Tidal volume	Increases by ≈40% compared to prepregnancy levels
Residual volume	Decreases by ≈20% compared to prepregnancy levels
Respiratory rate	No change
Minute ventilation	Increases by ≈40% compared to prepregnancy levels
Inspiratory reserve volume	Increases by ≈10% compared to prepregnancy levels
Expiratory reserve volume	Decreases by ≈30% compared to prepregnancy levels
FEV₁ (forced expiratory volume in 1 s)	No change
FEV₁/Forced vital capacity	No change
Functional residual capacity	Decreases by ≈20% compared to prepregnancy levels
Inspiratory capacity	Increases by ≈20% compared to prepregnancy levels
Total lung capacity	Decreases by ≈5% compared to prepregnancy levels