NORTHBROOK, Ill -- November 6, 2009 -- New research shows that during natural menstrual cycles, women with asthma who were not taking oral contraceptives (OC) had lower exhaled nitric oxide levels (eNO), a marker of airway inflammation associated with asthma, than women who were taking OC.
Furthermore, among women not using oral contraceptives, an increase in oestrogen levels was associated with a decrease in eNO, while an increase in progesterone was significantly associated with an increase in eNO.
Researchers speculate that OC may have a potential role in the management of premenopausal women with asthma.
For the study, researchers from McMaster University, Hamilton, Ontario, studied 17 women with asthma during their menstrual cycles. Of 534 potential daily visits, 526 (98.5%) were completed.
Women not using OC (n = 8) had higher mean eNO levels than women using OC (P <= .005).
In contrast, an increase in progesterone level of 0.5 nmol/L was significantly associated with an increase in eNO (P <= .05).
There were no significant associations between sex hormones and markers of asthma among women using OC.
Significant changes in asthma and atopy occur throughout the menstrual cycle, the authors wrote. Characteristics of asthma vary throughout the menstrual cycle in relation to changes in the levels of oestrogen or progesterone and this variation is attenuated in women using OC.
SOURCE: American College of Chest Physicians
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