Variability in the prevalence of premenstrual asthma.
Our aim is to analyse the differences in the prevalence of premenstrual asthma (PMA) according to a set of criteria, the relationship between them and the influence of asthma severity. The answer "Yes" to "Does your asthma get worse before menstruation?" was considered subjective PMA. A daily respiratory symptoms register of fertile asthmatic females was taken during two consecutive menstrual cycles. For the semi-objective diagnosis, an exacerbation of > or =20% was required in the symptoms register. Objective diagnosis was a premenstrual worsening of > or =20% of peak flow. We selected 103 patients. Subjective premenstrual deterioration was perceived in 43.7%. The semi-objective deterioration of symptoms in the first cycle occurred in 44.7%, and in 22.3% in both cycles. A total of 54.3% of females with semi-objective criteria in the first cycle perceived a subjective deterioration of symptoms, versus 35.1% of those without semi-objective criteria (p = 0.05). PMA was present at all levels of asthma severity, with no clear link to the degree of severity. The detection of PMA prevalence, the subjective perception of this deterioration and its presence at all levels of asthma severity lead us to urge research into possible premenstrual deterioration in all fertile asthmatic females.