Aim: The aim of this study was to evaluate the changes in lung function and breathing regulation parameters measured in women who did not suffer from any respiratory system disorders (in comparison with body mass index values obtained before pregnancy) in any particular trimester of pregnancy.
Methods: The study was carried out on 51 pregnant women aged 26.6 +/- 4.9 years and 40 healthy women (control group). Spirometry, flow-volume loop, respiratory resistance (RRS), and respiratory pattern were evaluated using computerized spirometer "Lungtest," Poland. The examinations were performed in the first, second, and third trimesters of pregnancy.
Results: The statistically significant differences during pregnancy were stated in cases of tidal volume (VT) and minute ventilation (MV) (whereas breath frequency was nearly on the same level), inspiratory drive (VT/TI) and also occlusion pressure (P0.1), RRS, and peak expiratory flow (PEF). We observed a correlation between BMI at the baseline with P0.1, MV, and VT/TI.
Conclusions: We conclude that BMI at the baseline seems to predict the increase in MV, occlusion pressure, and inspiratory drive. The fact that RRS values increase during pregnancy and both forced expiratory volume (FEV1) and FEV1% forced vital capacity (FVC) values remain at the same level may reflect the effect of the autonomous nervous system on the respiratory tract.