  Assessing the significance and implications of the recently established
Hubble tension requires the comprehensive identification, quantification, and
mitigation of uncertainties and/or biases affecting $H_0$ measurements. Here,
we investigate the previously overlooked distance scale bias resulting from the
interplay between redshift and Leavitt laws in an expanding Universe:
Redshift-Leavitt bias (RLB). Redshift dilates oscillation periods of pulsating
stars residing in supernova-host galaxies relative to periods of identical
stars residing in nearby (anchor) galaxies. Multiplying dilated $\log{P}$ with
Leavitt Law slopes leads to underestimated absolute magnitudes, overestimated
distance moduli, and a systematic error on $H_0$. Emulating the SH0ES distance
ladder, we estimate an associated $H_0$ bias of $(0.27 \pm 0.01)$% and obtain a
corrected $H_0 = (73.70 \pm 1.40) \rm{km s^{-1} Mpc^{-1}}$. RLB becomes
increasingly relevant as distance ladder calibrations pursue greater numbers of
ever more distant galaxies hosting both Cepheids (or Miras) and type-Ia
supernovae. The measured periods of oscillating stars can readily be corrected
for heliocentric redshift (e.g. of their host galaxies) in order to ensure
$H_0$ measurements free of RLB.
