Spirometry Profiles among Pregnant and Non-Pregnant African Women

Abstract

Background: Lung function tests are done to assess the working and possible mechanical deterioration of lungs, respiratory muscles, and chest wall. Spirometry is the 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 describe their differences. Methodology: This hospital-based 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.