RESUMO
Objectives: Oral contraceptive pills (OCPs) are hormonal pills used by females to prevent conception; they are a combination of estrogen and progestin. There is, however, compelling evidence that throughout the reproductive life of a woman, her airways are subject to the influence of the cyclical variations in sex hormones which occur in relation to circadian rhythms. The present study has been designed to investigate the effects of OCPs on airway resistance in terms of spirometric parameters in OCP users and nonusers. Materials and Methods: A total of 100 women (age: 20-40 years) ware selected for the present study. The subjects were provided with a one-month supply of OCPs. The constituents per tablet of MALA-N used were levonorgestrel 0.15 mg and ethinylestradiol 0.03 mg. Peak expiratory flow rate (PEFR), forced expiratory flow in expiring 25-75% air (FEF 25-75), forced expiratory volume percentage in one second (FEV1% or FEV1/FVC), forced vital capacity (FVC), and forced expiratory volume in one second (FEV1) were recorded. Results: In our study, the FEF 25-75and PEFR increased significantly in OCP users, showing that these hormone pills decrease the resistance offered by small bronchioles.