Lung function tests in bronchial asthma during and after pregnancy.

Respiratory function tests (forced vital capacity and forced expiratory volume in one second) were performed serially in pregnancy, the puerperium, and at least six weeks post partum in 27 patients with a history of asthma and in 12 control subjects. Eleven asthmatic patients with spirometric evidence of respiratory obstruction in pregnancy on at least one occasion were considered to have active disease. This group had significantly impaired respiratory function tests when compared to controls. The remaining 16 asthmatic patients were considered to be in remission. No changes in respiratory function tests attributable to pregnancy could be demonstrated in the asthma or control groups. Patients with active asthma tended to have smaller babies than patients with asthma in remission or the control patients.