Background Spirometry is a commonly used lung function test. It assesses respiratory functions by measuring the air volume and the rate at which a person can exhale from lungs filled to their total capacity. The most helpful spirometry parameters are: forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak expiratory flow (PEF). Pregnancy derives an altered physiological state due to hormonal and anatomical changes that affect the respiratory system. Despite that, spirometry is less commonly done during pregnancy, and if done, test results are evaluated against non-pregnancy references. Objective This study aimed to explore spirometry profiles in pregnant and non-pregnant women and describe their differences. Methodology This cross-sectional study involved age-matched pregnant and non-pregnant participants recruited from Mnazi Moja ANC and Muhimbili University (MUHAS). A digital spirometer was used to assess respiratory function. Data were entered and analyzed using SPSS version 23. The mean spirometry values of pregnant participants were compared to those of non-pregnant participants using an independent sample t-test. A p-value of < 0.05 was considered statistically significant. Results The study included 92 pregnant and 98 non-pregnant participants subjected to spirometry. Both FVC and FEV1 values were significantly lower in pregnant than in non-pregnant participants (2.7 ± 0.5 L vs. 2.9 ± 0.5 L; p < 0.01 and 2.2 ± 0.4 L vs. 2.5 ± 0.4 L; p < 0.01 respectively). In addition, pregnant participants had significantly lower mean PEF values than their non-pregnant counterparts (303 ± 84 L/min versus 353 ± 64 L/min; p < 0.01). Conclusion Spirometry test values are lower in pregnancy than in non-pregnant participants. Recommendations Interpreting the spirometry test values of pregnant women using references obtained from non-pregnant women may be inappropriate. Future studies should evaluate the appropriateness of predicting spirometry values of pregnant women using reference equations derived from non-pregnant women.

Introduction Despite the prevalence of respiratory disorders in the gravid state, and the crucial role of spirometry in respiratory medicine, its utility for assessing lung function during pregnancy remains infrequent. Putative reasons for this include reservations regarding spirometry performance and its potential influence on test outcomes, although the literature documenting such concerns is insufficient. This study sought to evaluate whether variations in spirometry test performance could impact the diagnosis of pulmonary function patterns throughout gestation. Methods We used spirometry data from a cross-sectional study of 120 pregnant and 114 non-pregnant women who underwent spirometry with uniform instructions given to all subjects. Data were subjected to chi-square testing and subsequently evaluated through logistic regression analysis. Results The acceptable performance rate among pregnant participants was 77.3%, with the most common quality grade being C (37.5%). Pregnant individuals exhibited 2.1 times the odds of achieving a B grade (p=0.037, 95% CI=1.0-4.2) and 4.1 times the odds of achieving an F grade (p=0.02, 95% CI=1.6-9.9) instead of an A grade. Additionally, they manifested 2.9 times the odds of generating unsatisfactory performance (p=0.007, 95% CI=1.3-6.1) compared to non-pregnant participants. Also, pregnant participants displayed 2.5 times the odds of exhibiting a restrictive pattern (p=0.021, 95% CI=1.1-5.7); but pattern classification was not associated with quality grades. Conclusion Despite the higher likelihood of suboptimal spirometry quality, the observed pattern classification remains as expected physiologically, suggesting that spirometry is still a valid tool for assessing lung function in pregnancy.

Background: Lung function tests are done to assess the working and possible mechanical deterioration of lungs, respiratory muscles, and chest wall. Spirometry is a commonly used test. Pregnancy derives an altered physiological state due to accompanied hormonal and anatomical changes that affect the respiratory system. Despite that, spirometry is rarely done in pregnancy, and if done test results are compared against non-pregnancy references.Objective: This study aimed at determining spirometry profiles in pregnant and non-pregnant women and describing their differences.Methodology: This cross-sectional study was conducted at Mnazi Mmoja antenatal clinic where pregnant women who met the inclusion criteria were randomly recruited. Also, non-pregnant women were recruited from MUHAS as controls. Lung function was assessed using a digital spirometer (EasyOne®) while adhering to standard operating procedures (SOPs) and infection prevention protocols. Data were entered and analyzed using SPSS version 23. The means of spirometry parameters of pregnant women were compared to parameters of non-pregnant women using an independent sample t-test. The level of significance was set to < 0.05 p-value.Results: A total of 92 pregnant and 98 non-pregnant women were subjected to spirometry. Mean FVC (p <0.01), FEV1 (p <0.01), and PEF (p <0.01) of pregnant women were significantly lower than non-pregnant women.Conclusion: Spirometry test values obtained from pregnant women were lower than those obtained from non-pregnant controls.Recommendations: Spirometry test values of pregnant women should be carefully interpreted against non-pregnancy references otherwise can cause underestimation of their values, and hence over-hospitalization. There is also a need to evaluate the accuracy of non-pregnancy spirometry reference equations for predicting test values among pregnant women.