Respiratory function in children of asthmatic mothers.

OBJECTIVE To evaluate lung function and clinical manifestations suggestive of asthma in children of mothers with a reported medical diagnosis of asthma. METHODS An observational cross-sectional analytical study nested in a cohort of 4,757 pregnant women. A total of 86 six-year-old children were evaluated, born to mothers with a medical diagnosis of asthma before pregnancy. Information was collected regarding clinical symptoms of atopy and respiratory diseases, as well as socioeconomic and exposure variables; the children were submitted to spirometry. RESULTS Spirometric alterations were observed in 30.3% of cases, with a prevalence of asthma in those who had an obstructive pattern. 9.3% of the children had a previous medical diagnosis of asthma; however, the established diagnosis based on the presence and frequency of asthma symptoms was 18.6%. Of the 86 participating children, 37.2% had a score of five or more points in the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, which was associated with spirometry alterations (p=0.002). After multiple logistic regression analysis, higher paternal education, higher number of bedrooms in the family's home, and mother who did not have "wheezing" episodes during pregnancy were statistically significant as protective factors for the presence of respiratory disorder detected by spirometry. CONCLUSIONS The frequency of spirometry alterations in children of asthmatic mothers was high; the restrictive pattern was more often observed that the obstructive. There was a higher incidence of obstructive test results in those who presented clinical symptoms of asthma, with a higher frequency of clinical diagnosis of asthma than that found in the literature.