The impacts of parity on spirometric parameters: a systematic review.

Introduction: The relationship between parity and health outcomes has been debated in the scientific literature in terms of 'selection-pressure'. However, no previous review has raised the impacts of parity on spirometric parameters. This Systematic Review aimed to review the impacts of parity on spirometric parameters.Areas covered: PubMed and Scopus were searched on October 1st, 2020, using the combination of the following two medical subject headings: 'Parity' and 'Respiratory Function Tests'. Only original articles published in English/French were retained. Ten studies investigated the impacts of parity on spirometric parameters: six included healthy females, three involved unhealthy females [chronic obstructive pulmonary disease, defect in protease inhibitor, and some other conditions] and one included a mixed population of healthy/unhealthy females. The studies reported conflicting results: no impact, positive impact (multiparity is associated with larger forced-expiratory-volume in one second, forced- and slow- vital-capacity, and inspiratory-capacity), or negative impact (multiparous females has lower bronchial flows, higher static volumes, an accelerated lung-aging, a tendency to an obstructive-ventilatory-defect and/or to lung-hyperinflation, and increased protease inhibitor levels).Expert opinion: The ten studies presented some limitations that made data interpretation relatively difficult. Future research to identify the 'real' impact of parity on spirometric parameters are therefore encouraged.