The Relationship Between Contraceptive Use and Respiratory Function in Women: A Systematic Review.

Hormonal contraceptives are widely used, but their effects on respiratory health remain underexplored. This systematic review examined the impact of oral contraceptive pills (OCPs) on pulmonary function, with an emphasis on asthma-related outcomes and underlying mechanisms. MEDLINE (PubMed), EMBASE (Ovid), CINAHL, AMED, SPORTDiscus, and PEDro were searched from January 2000 to December 2024. Pulmonary outcomes assessed included PEFR, FEV, airway hyperresponsiveness, and exhaled nitric oxide levels. Twelve peer-reviewed studies were included. Most studies reported that OCPs do not impair lung function and may even improve respiratory parameters. Women using OCPs showed enhanced peak expiratory flow and reduced symptom variability, particularly in asthma and cystic fibrosis. Potential mechanisms include the stabilization of airway reactivity and modulation of inflammatory pathways. Heterogeneity across study populations and contraceptive types limited a meta-analysis, and few studies stratified outcomes by hormonal composition or comorbidities. Hormonal contraceptives may provide protective or regulatory effects on pulmonary function in specific populations. Larger precision-based studies are needed to clarify mechanisms and guide contraceptive counseling for women with respiratory conditions.