BackgroundCystic Fibrosis (CF) is a genetic disease with equal prevalence across sexes. However, women present worse lung function with faster function decline, earlier onset of bacterial colonization, more frequent pulmonary exacerbations (PE), greater bronchial hyper-responsiveness, and higher mortality rates after puberty than men. The etiology of this gender disparity remains elusive but female hormones have been implicated in several studies.Case presentationA 20-year-old female with CF with severe recurrent PE, always related to the menstrual cycle since menarche, combined with lung function decline requiring multiple courses of intravenous antibiotics. We report the cessation of PE and recovery of pulmonary function following the insertion of a subcutaneous implant with 68 mg of etonogestrel (Implanon®, Organon Española S.A. Laboratories, Madrid, Spain).ConclusionOur case report supports the key role of female hormones in the development of PE and in the decline of lung function in a woman with CF. When appropriate, hormonal manipulation through contraceptive methods should be considered as potential treatment.