A prospective cohort study of pulmonary function during pregnancy in women with and without asthma

Abstract

Background and objective: Pregnancy alters the severity of asthma unpredictably. Uncertainty still exists about longitudinal changes in pulmonary function during pregnancy in both healthy and asthmatic women. This study aimed to compare pulmonary function changes during pregnancy in healthy and asthmatic women and to determine the relationship between pulmonary function and asthma-related quality of life during pregnancy. A secondary aim was to investigate the application of forced expiratory volume in 6 s (FEV₆) for monitoring asthma during pregnancy. Methods: Pregnant women with (n = 20) and without asthma (n = 20) had pulmonary function tests at 8–20, 21–28 and 29–40 weeks gestation. Those with asthma also completed the Asthma Control Questionnaire (ACQ) and mini Asthma Quality of Life Questionnaire (mAQLQ) at each visit. Results: Pulmonary function declined in both groups at follow-up #1 (more markedly in those with asthma) but then improved at follow-up #2 (more markedly in those with asthma). In those with asthma, ACQ scores increased, while mAQLQ scores declined at follow-up #1; whilst at follow-up #2 these changes were in the opposite direction. FEV₆ and forced vital capacity (FVC) were highly correlated (r = 0.88, p < 0.01) in asthmatics. Conclusions: Pulmonary function changes during second and third trimesters were more pronounced in asthmatics than in healthy women. FEV₆ monitoring may assist pregnant women and their health professionals in optimizing asthma management. The changes in pulmonary function in women with asthma were not significantly associated with changes in asthma control or asthma-related quality of life.

• Asthma
• pregnancy
• pulmonary function
• spirometry

Acknowledgements

The authors wish to thank the study participants, staff at Mercy Hospital for Women and the Respiratory Laboratory Austin Health, Heidelberg, Victoria.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Dr George has received in-kind support from Vitalograph, the manufacturers of COPD-6, for this research. Prof. Abramson and Dr George have held investigator-initiated research grants from Pfizer and Boehringer Ingelheim for unrelated research. Prof. Abramson has undertaken an unrelated consultancy for Astra Zeneca and received assistance with conference attendance from Boehringer-Ingelheim and Sanofi. Prof. McDonald has participated in advisory boards and educational meetings for Boehringer Ingelheim, Novartis, GSK and AstraZeneca.