Conclusions
Women with asthma experience cyclic changes in airflow as well as gas transfer and membrane diffusing capacity supportive of a hormonal effect on lung function.
Methods
Twenty-three women, 13 with asthma and 10 healthy control subjects, were evaluated over the menstrual cycle with weekly measures of spirometry, gas transfer, nitric oxide, hemoglobin, factors affecting hemoglobin binding affinity, and proangiogenic factors. Measurements and main
Results
Airflow and lung diffusing capacity varied over the menstrual cycle with peak levels during menses that subsequently declined to nadir in early luteal phase. In contrast to healthy women, changes in lung diffusing capacity (DL(CO)) were associated with changes in membrane diffusing capacity and DL(CO) was not related to proangiogenic factors. DL(CO) did not differ between the two groups, although methemoglobin and carboxyhemoglobin were higher in women with asthma than in healthy women. Conclusions: Women with asthma experience cyclic changes in airflow as well as gas transfer and membrane diffusing capacity supportive of a hormonal effect on lung function.