How do respiratory state and measurement method affect bra size calculations?

Objectives: To investigate the effects of respiratory state and measurement method on bra size calculation.
Methods: The bra sizes of 16 large-breasted women were measured during two respiratory states, end voluntary inspiration and relaxed voluntary expiration, and using two sizing methods, which were compared against subject-reported bra sizes.
Results: Both respiratory state and measurement method significantly affected bra size estimations, whereby measuring chest circumference during inspiration increased both band and decreased cup size. However, whereas bra size calculated using the standard method differed significantly from subject-reported bra size, cup size calculated using the breast hemi-circumference method did not differ significantly from subject-reported cup size.
Conclusions: As respiratory state significantly affects bra sizes, it should be standardised during bra size measurements. A more valid and reliable bra sizing method should be developed, possibly using the breast hemi-circumference method for cup size estimations and raw under-bust chest circumference values for band size.