Preterm birth (PTB) was induced in pregnant mice via intrauterine lipopolysaccharide (LPS) injection. Dams receiving no treatment delivered prematurely with no surviving pups. To compare the efficacy of local and systemic drug exposure in preventing PTB, one cohort of dams received a vaginal administration of a mucus penetrating nanosuspension (NS) formulation at the time of PTB induction, and a second cohort received an intraperitoneal (I.P.) injection of free drug. The cohort receiving vaginally administered mucus penetrating NS delivered live pups at term, whereas the cohort receiving I.P. drug delivered prematurely with no surviving offspring. Adapted from Zierden, et al., Copyright 2020, with permission from American Association for the Advancement of Science [28].